/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2007 by Janne Karhu.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/editors/physics/particle_edit.c
 *  \ingroup edphys
 */

#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <assert.h>

#include "MEM_guardedalloc.h"

#include "DNA_scene_types.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_view3d_types.h"
#include "DNA_screen_types.h"
#include "DNA_space_types.h"

#include "BLI_math.h"
#include "BLI_lasso_2d.h"
#include "BLI_listbase.h"
#include "BLI_string.h"
#include "BLI_kdtree.h"
#include "BLI_rand.h"
#include "BLI_task.h"
#include "BLI_utildefines.h"

#include "BKE_bvhutils.h"
#include "BKE_context.h"
#include "BKE_global.h"
#include "BKE_main.h"
#include "BKE_mesh.h"
#include "BKE_mesh_runtime.h"
#include "BKE_modifier.h"
#include "BKE_object.h"
#include "BKE_particle.h"
#include "BKE_pointcache.h"
#include "BKE_report.h"
#include "BKE_scene.h"

#include "DEG_depsgraph.h"

#include "BIF_gl.h"

#include "ED_object.h"
#include "ED_physics.h"
#include "ED_mesh.h"
#include "ED_particle.h"
#include "ED_screen.h"
#include "ED_select_utils.h"
#include "ED_view3d.h"

#include "GPU_immediate.h"
#include "GPU_immediate_util.h"
#include "GPU_state.h"

#include "UI_resources.h"

#include "WM_api.h"
#include "WM_types.h"
#include "WM_message.h"
#include "WM_toolsystem.h"

#include "RNA_access.h"
#include "RNA_define.h"

#include "DEG_depsgraph_query.h"

#include "PIL_time_utildefines.h"

#include "physics_intern.h"

#include "particle_edit_utildefines.h"

/**************************** utilities *******************************/

bool PE_poll(bContext *C)
{
	Scene *scene = CTX_data_scene(C);
	Object *ob = CTX_data_active_object(C);

	if (!scene || !ob || !(ob->mode & OB_MODE_PARTICLE_EDIT)) {
		return 0;
	}
	return (PE_get_current(scene, ob) != NULL);
}

bool PE_hair_poll(bContext *C)
{
	Scene *scene = CTX_data_scene(C);
	Object *ob = CTX_data_active_object(C);
	PTCacheEdit *edit;

	if (!scene || !ob || !(ob->mode & OB_MODE_PARTICLE_EDIT)) {
		return 0;
	}
	edit = PE_get_current(scene, ob);

	return (edit && edit->psys);
}

bool PE_poll_view3d(bContext *C)
{
	ScrArea *sa = CTX_wm_area(C);
	ARegion *ar = CTX_wm_region(C);

	return (PE_poll(C) &&
	        (sa && sa->spacetype == SPACE_VIEW3D) &&
	        (ar && ar->regiontype == RGN_TYPE_WINDOW));
}

void PE_free_ptcache_edit(PTCacheEdit *edit)
{
	POINT_P;

	if (edit == 0) return;

	if (edit->points) {
		LOOP_POINTS {
			if (point->keys)
				MEM_freeN(point->keys);
		}

		MEM_freeN(edit->points);
	}

	if (edit->mirror_cache)
		MEM_freeN(edit->mirror_cache);

	if (edit->emitter_cosnos) {
		MEM_freeN(edit->emitter_cosnos);
		edit->emitter_cosnos = 0;
	}

	if (edit->emitter_field) {
		BLI_kdtree_free(edit->emitter_field);
		edit->emitter_field = 0;
	}

	psys_free_path_cache(edit->psys, edit);

	MEM_freeN(edit);
}

/************************************************/
/*			Edit Mode Helpers					*/
/************************************************/

int PE_start_edit(PTCacheEdit *edit)
{
	if (edit) {
		edit->edited = 1;
		if (edit->psys)
			edit->psys->flag |= PSYS_EDITED;
		return 1;
	}

	return 0;
}

ParticleEditSettings *PE_settings(Scene *scene)
{
	return scene->toolsettings ? &scene->toolsettings->particle : NULL;
}

static float pe_brush_size_get(const Scene *UNUSED(scene), ParticleBrushData *brush)
{
	// here we can enable unified brush size, needs more work...
	// UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;
	// float size = (ups->flag & UNIFIED_PAINT_SIZE) ? ups->size : brush->size;

	return brush->size * U.pixelsize;
}

PTCacheEdit *PE_get_current_from_psys(ParticleSystem *psys)
{
	if (psys->part && psys->part->type == PART_HAIR) {
		if ((psys->flag & PSYS_HAIR_DYNAMICS) != 0 &&
		    (psys->pointcache->flag & PTCACHE_BAKED) != 0)
		{
			return psys->pointcache->edit;
		}
		else {
			return psys->edit;
		}
	}
	else if (psys->pointcache->flag & PTCACHE_BAKED) {
		return psys->pointcache->edit;
	}
	return NULL;
}

/* NOTE: Similar to creation of edit, but only updates pointers in the
 * existing struct.
 */
static void pe_update_hair_particle_edit_pointers(PTCacheEdit *edit)
{
	ParticleSystem *psys = edit->psys;
	ParticleData *pa = psys->particles;
	for (int p = 0; p < edit->totpoint; p++) {
		PTCacheEditPoint *point = &edit->points[p];
		HairKey *hair_key = pa->hair;
		for (int k = 0; k < point->totkey; k++) {
			PTCacheEditKey *key = &point->keys[k];
			key->co = hair_key->co;
			key->time = &hair_key->time;
			key->flag = hair_key->editflag;
			if (!(psys->flag & PSYS_GLOBAL_HAIR)) {
				key->flag |= PEK_USE_WCO;
				hair_key->editflag |= PEK_USE_WCO;
			}
			hair_key++;
		}
		pa++;
	}
}

/* always gets at least the first particlesystem even if PSYS_CURRENT flag is not set
 *
 * note: this function runs on poll, therefor it can runs many times a second
 * keep it fast! */
static PTCacheEdit *pe_get_current(
        Depsgraph *depsgraph, Scene *scene, Object *ob, int create)
{
	ParticleEditSettings *pset = PE_settings(scene);
	PTCacheEdit *edit = NULL;
	ListBase pidlist;
	PTCacheID *pid;

	if (pset == NULL || ob == NULL)
		return NULL;

	pset->scene = scene;
	pset->object = ob;

	BKE_ptcache_ids_from_object(&pidlist, ob, NULL, 0);

	/* in the case of only one editable thing, set pset->edittype accordingly */
	if (BLI_listbase_is_single(&pidlist)) {
		pid = pidlist.first;
		switch (pid->type) {
			case PTCACHE_TYPE_PARTICLES:
				pset->edittype = PE_TYPE_PARTICLES;
				break;
			case PTCACHE_TYPE_SOFTBODY:
				pset->edittype = PE_TYPE_SOFTBODY;
				break;
			case PTCACHE_TYPE_CLOTH:
				pset->edittype = PE_TYPE_CLOTH;
				break;
		}
	}

	for (pid = pidlist.first; pid; pid = pid->next) {
		if (pset->edittype == PE_TYPE_PARTICLES && pid->type == PTCACHE_TYPE_PARTICLES) {
			ParticleSystem *psys = pid->calldata;

			if (psys->flag & PSYS_CURRENT) {
				if (psys->part && psys->part->type == PART_HAIR) {
					if (psys->flag & PSYS_HAIR_DYNAMICS && psys->pointcache->flag & PTCACHE_BAKED) {
						if (create && !psys->pointcache->edit)
							PE_create_particle_edit(depsgraph, scene, ob, pid->cache, NULL);
						edit = pid->cache->edit;
					}
					else {
						if (create && !psys->edit) {
							if (psys->flag & PSYS_HAIR_DONE) {
								PE_create_particle_edit(depsgraph, scene, ob, NULL, psys);
							}
						}
						edit = psys->edit;
					}
				}
				else {
					if (create && pid->cache->flag & PTCACHE_BAKED && !pid->cache->edit)
						PE_create_particle_edit(depsgraph, scene, ob, pid->cache, psys);
					edit = pid->cache->edit;
				}

				break;
			}
		}
		else if (pset->edittype == PE_TYPE_SOFTBODY && pid->type == PTCACHE_TYPE_SOFTBODY) {
			if (create && pid->cache->flag & PTCACHE_BAKED && !pid->cache->edit) {
				pset->flag |= PE_FADE_TIME;
				// NICE TO HAVE but doesn't work: pset->brushtype = PE_BRUSH_COMB;
				PE_create_particle_edit(depsgraph, scene, ob, pid->cache, NULL);
			}
			edit = pid->cache->edit;
			break;
		}
		else if (pset->edittype == PE_TYPE_CLOTH && pid->type == PTCACHE_TYPE_CLOTH) {
			if (create && pid->cache->flag & PTCACHE_BAKED && !pid->cache->edit) {
				pset->flag |= PE_FADE_TIME;
				// NICE TO HAVE but doesn't work: pset->brushtype = PE_BRUSH_COMB;
				PE_create_particle_edit(depsgraph, scene, ob, pid->cache, NULL);
			}
			edit = pid->cache->edit;
			break;
		}
	}

	if (edit) {
		edit->pid = *pid;
		if (edit->flags & PT_CACHE_EDIT_UPDATE_PARTICLE_FROM_EVAL) {
			if (edit->psys != NULL) {
				psys_copy_particles(edit->psys, edit->psys_eval);
				pe_update_hair_particle_edit_pointers(edit);
			}
			edit->flags &= ~PT_CACHE_EDIT_UPDATE_PARTICLE_FROM_EVAL;
		}
	}

	BLI_freelistN(&pidlist);

	return edit;
}

PTCacheEdit *PE_get_current(Scene *scene, Object *ob)
{
	return pe_get_current(NULL, scene, ob, 0);
}

PTCacheEdit *PE_create_current(Depsgraph *depsgraph, Scene *scene, Object *ob)
{
	return pe_get_current(depsgraph, scene, ob, 1);
}

void PE_current_changed(Depsgraph *depsgraph, Scene *scene, Object *ob)
{
	if (ob->mode == OB_MODE_PARTICLE_EDIT) {
		PE_create_current(depsgraph, scene, ob);
	}
}

void PE_hide_keys_time(Scene *scene, PTCacheEdit *edit, float cfra)
{
	ParticleEditSettings *pset = PE_settings(scene);
	POINT_P; KEY_K;


	if (pset->flag & PE_FADE_TIME && pset->selectmode == SCE_SELECT_POINT) {
		LOOP_POINTS {
			LOOP_KEYS {
				if (fabsf(cfra - *key->time) < pset->fade_frames)
					key->flag &= ~PEK_HIDE;
				else {
					key->flag |= PEK_HIDE;
					//key->flag &= ~PEK_SELECT;
				}
			}
		}
	}
	else {
		LOOP_POINTS {
			LOOP_KEYS {
				key->flag &= ~PEK_HIDE;
			}
		}
	}
}

static int pe_x_mirror(Object *ob)
{
	if (ob->type == OB_MESH)
		return (((Mesh *)ob->data)->editflag & ME_EDIT_MIRROR_X);

	return 0;
}

/****************** common struct passed to callbacks ******************/

typedef struct PEData {
	ViewContext vc;

	const bContext *context;
	Main *bmain;
	Scene *scene;
	ViewLayer *view_layer;
	Object *ob;
	Mesh *mesh;
	PTCacheEdit *edit;
	BVHTreeFromMesh shape_bvh;
	Depsgraph *depsgraph;

	RNG *rng;

	const int *mval;
	const rcti *rect;
	float rad;
	float dist;
	float dval;
	int select;
	eSelectOp sel_op;

	float *dvec;
	float combfac;
	float pufffac;
	float cutfac;
	float smoothfac;
	float weightfac;
	float growfac;
	int totrekey;

	int invert;
	int tot;
	float vec[3];

	int select_action;
	int select_toggle_action;
} PEData;

static void PE_set_data(bContext *C, PEData *data)
{
	memset(data, 0, sizeof(*data));

	data->bmain = CTX_data_main(C);
	data->scene = CTX_data_scene(C);
	data->view_layer = CTX_data_view_layer(C);
	data->ob = CTX_data_active_object(C);
	data->depsgraph = CTX_data_depsgraph(C);
	data->edit = PE_get_current(data->scene, data->ob);
}

static void PE_set_view3d_data(bContext *C, PEData *data)
{
	PE_set_data(C, data);

	ED_view3d_viewcontext_init(C, &data->vc);

	if (V3D_IS_ZBUF(data->vc.v3d)) {
		if (data->vc.v3d->flag & V3D_INVALID_BACKBUF) {
			/* needed or else the draw matrix can be incorrect */
			view3d_operator_needs_opengl(C);

			ED_view3d_backbuf_validate(&data->vc);
			/* we may need to force an update here by setting the rv3d as dirty
			 * for now it seems ok, but take care!:
			 * rv3d->depths->dirty = 1; */
			ED_view3d_depth_update(data->vc.ar);
		}
	}
}

static bool PE_create_shape_tree(PEData *data, Object *shapeob)
{
	Mesh *mesh = BKE_object_get_evaluated_mesh(data->depsgraph, shapeob);

	memset(&data->shape_bvh, 0, sizeof(data->shape_bvh));

	if (!mesh) {
		return false;
	}

	return (BKE_bvhtree_from_mesh_get(&data->shape_bvh, mesh, BVHTREE_FROM_LOOPTRI, 4) != NULL);
}

static void PE_free_shape_tree(PEData *data)
{
	free_bvhtree_from_mesh(&data->shape_bvh);
}

static void PE_create_random_generator(PEData *data)
{
	uint rng_seed = (uint)(PIL_check_seconds_timer_i() & UINT_MAX);
	rng_seed ^= POINTER_AS_UINT(data->ob);
	rng_seed ^= POINTER_AS_UINT(data->edit);
	data->rng = BLI_rng_new(rng_seed);
}

static void PE_free_random_generator(PEData *data)
{
	if (data->rng != NULL) {
		BLI_rng_free(data->rng);
		data->rng = NULL;
	}
}

/*************************** selection utilities *******************************/

static bool key_test_depth(PEData *data, const float co[3], const int screen_co[2])
{
	View3D *v3d = data->vc.v3d;
	ViewDepths *vd = data->vc.rv3d->depths;
	float depth;

	/* nothing to do */
	if (!V3D_IS_ZBUF(v3d))
		return true;

	/* used to calculate here but all callers have  the screen_co already, so pass as arg */
#if 0
	if (ED_view3d_project_int_global(data->vc.ar, co, screen_co,
	                                 V3D_PROJ_TEST_CLIP_BB | V3D_PROJ_TEST_CLIP_WIN | V3D_PROJ_TEST_CLIP_NEAR) != V3D_PROJ_RET_OK)
	{
		return 0;
	}
#endif

	/* check if screen_co is within bounds because brush_cut uses out of screen coords */
	if (screen_co[0] >= 0 && screen_co[0] < vd->w && screen_co[1] >= 0 && screen_co[1] < vd->h) {
		BLI_assert(vd && vd->depths);
		/* we know its not clipped */
		depth = vd->depths[screen_co[1] * vd->w + screen_co[0]];
	}
	else
		return 0;

	float win[3];
	ED_view3d_project(data->vc.ar, co, win);

	if (win[2] - 0.00001f > depth)
		return 0;
	else
		return 1;
}

static bool key_inside_circle(PEData *data, float rad, const float co[3], float *distance)
{
	float dx, dy, dist;
	int screen_co[2];

	/* TODO, should this check V3D_PROJ_TEST_CLIP_BB too? */
	if (ED_view3d_project_int_global(data->vc.ar, co, screen_co, V3D_PROJ_TEST_CLIP_WIN) != V3D_PROJ_RET_OK) {
		return 0;
	}

	dx = data->mval[0] - screen_co[0];
	dy = data->mval[1] - screen_co[1];
	dist = sqrtf(dx * dx + dy * dy);

	if (dist > rad)
		return 0;

	if (key_test_depth(data, co, screen_co)) {
		if (distance)
			*distance = dist;

		return 1;
	}

	return 0;
}

static bool key_inside_rect(PEData *data, const float co[3])
{
	int screen_co[2];

	if (ED_view3d_project_int_global(data->vc.ar, co, screen_co, V3D_PROJ_TEST_CLIP_WIN) != V3D_PROJ_RET_OK) {
		return 0;
	}

	if (screen_co[0] > data->rect->xmin && screen_co[0] < data->rect->xmax &&
	    screen_co[1] > data->rect->ymin && screen_co[1] < data->rect->ymax)
	{
		return key_test_depth(data, co, screen_co);
	}

	return 0;
}

static bool key_inside_test(PEData *data, const float co[3])
{
	if (data->mval)
		return key_inside_circle(data, data->rad, co, NULL);
	else
		return key_inside_rect(data, co);
}

static bool point_is_selected(PTCacheEditPoint *point)
{
	KEY_K;

	if (point->flag & PEP_HIDE)
		return 0;

	LOOP_SELECTED_KEYS {
		return 1;
	}

	return 0;
}

/*************************** iterators *******************************/

typedef void (*ForPointFunc)(PEData *data, int point_index);
typedef void (*ForKeyFunc)(PEData *data, int point_index, int key_index, bool is_inside);
typedef void (*ForKeyMatFunc)(PEData *data, float mat[4][4], float imat[4][4], int point_index, int key_index, PTCacheEditKey *key);

enum eParticleSelectFlag {
	PSEL_NEAREST = (1 << 0),
	PSEL_ALL_KEYS = (1 << 1),
};

static void for_mouse_hit_keys(PEData *data, ForKeyFunc func, const enum eParticleSelectFlag flag)
{
	ParticleEditSettings *pset = PE_settings(data->scene);
	PTCacheEdit *edit = data->edit;
	POINT_P; KEY_K;
	int nearest_point, nearest_key;
	float dist = data->rad;

	/* in path select mode we have no keys */
	if (pset->selectmode == SCE_SELECT_PATH)
		return;

	nearest_point = -1;
	nearest_key = -1;

	LOOP_VISIBLE_POINTS {
		if (pset->selectmode == SCE_SELECT_END) {
			if (point->totkey) {
				/* only do end keys */
				key = point->keys + point->totkey - 1;

				if (flag & PSEL_NEAREST) {
					if (key_inside_circle(data, dist, KEY_WCO, &dist)) {
						nearest_point = p;
						nearest_key = point->totkey - 1;
					}
				}
				else {
					const bool is_inside = key_inside_test(data, KEY_WCO);
					if (is_inside || (flag & PSEL_ALL_KEYS)) {
						func(data, p, point->totkey - 1, is_inside);
					}
				}
			}
		}
		else {
			/* do all keys */
			LOOP_VISIBLE_KEYS {
				if (flag & PSEL_NEAREST) {
					if (key_inside_circle(data, dist, KEY_WCO, &dist)) {
						nearest_point = p;
						nearest_key = k;
					}
				}
				else {
					const bool is_inside = key_inside_test(data, KEY_WCO);
					if (is_inside || (flag & PSEL_ALL_KEYS)) {
						func(data, p, k, is_inside);
					}
				}
			}
		}
	}

	/* do nearest only */
	if (flag & PSEL_NEAREST) {
		if (nearest_point != -1) {
			func(data, nearest_point, nearest_key, true);
		}
	}
}

static void foreach_mouse_hit_point(PEData *data, ForPointFunc func, int selected)
{
	ParticleEditSettings *pset = PE_settings(data->scene);
	PTCacheEdit *edit = data->edit;
	POINT_P; KEY_K;

	/* all is selected in path mode */
	if (pset->selectmode == SCE_SELECT_PATH)
		selected = 0;

	LOOP_VISIBLE_POINTS {
		if (pset->selectmode == SCE_SELECT_END) {
			if (point->totkey) {
				/* only do end keys */
				key = point->keys + point->totkey - 1;

				if (selected == 0 || key->flag & PEK_SELECT)
					if (key_inside_circle(data, data->rad, KEY_WCO, &data->dist))
						func(data, p);
			}
		}
		else {
			/* do all keys */
			LOOP_VISIBLE_KEYS {
				if (selected == 0 || key->flag & PEK_SELECT) {
					if (key_inside_circle(data, data->rad, KEY_WCO, &data->dist)) {
						func(data, p);
						break;
					}
				}
			}
		}
	}
}

typedef struct KeyIterData {
	PEData *data;
	PTCacheEdit *edit;
	int selected;
	ForKeyMatFunc func;
} KeyIterData;

static void foreach_mouse_hit_key_iter(
        void *__restrict iter_data_v,
        const int iter,
        const ParallelRangeTLS *__restrict UNUSED(tls))
{
	KeyIterData *iter_data = (KeyIterData *)iter_data_v;
	PEData *data = iter_data->data;
	PTCacheEdit *edit = data->edit;
	PTCacheEditPoint *point = &edit->points[iter];
	if (point->flag & PEP_HIDE) {
		return;
	}
	ParticleSystem *psys = edit->psys;
	ParticleSystemModifierData *psmd_eval = iter_data->edit->psmd_eval;
	ParticleEditSettings *pset = PE_settings(data->scene);
	const int selected = iter_data->selected;
	float mat[4][4], imat[4][4];
	unit_m4(mat);
	unit_m4(imat);
	if (pset->selectmode == SCE_SELECT_END) {
		if (point->totkey) {
			/* only do end keys */
			PTCacheEditKey *key = point->keys + point->totkey - 1;

			if (selected == 0 || key->flag & PEK_SELECT) {
				if (key_inside_circle(data, data->rad, KEY_WCO, &data->dist)) {
					if (edit->psys && !(edit->psys->flag & PSYS_GLOBAL_HAIR)) {
						psys_mat_hair_to_global(data->ob, psmd_eval->mesh_final, psys->part->from, psys->particles + iter, mat);
						invert_m4_m4(imat, mat);
					}
					iter_data->func(data, mat, imat, iter, point->totkey - 1, key);
				}
			}
		}
	}
	else {
		/* do all keys */
		PTCacheEditKey *key;
		int k;
		LOOP_VISIBLE_KEYS {
			if (selected == 0 || key->flag & PEK_SELECT) {
				if (key_inside_circle(data, data->rad, KEY_WCO, &data->dist)) {
					if (edit->psys && !(edit->psys->flag & PSYS_GLOBAL_HAIR)) {
						psys_mat_hair_to_global(data->ob, psmd_eval->mesh_final, psys->part->from, psys->particles + iter, mat);
						invert_m4_m4(imat, mat);
					}
					iter_data->func(data, mat, imat, iter, k, key);
				}
			}
		}
	}
}

static void foreach_mouse_hit_key(PEData *data, ForKeyMatFunc func, int selected)
{
	PTCacheEdit *edit = data->edit;
	ParticleEditSettings *pset = PE_settings(data->scene);
	/* all is selected in path mode */
	if (pset->selectmode == SCE_SELECT_PATH) {
		selected = 0;
	}

	KeyIterData iter_data;
	iter_data.data = data;
	iter_data.edit = edit;
	iter_data.selected = selected;
	iter_data.func = func;

	ParallelRangeSettings settings;
	BLI_parallel_range_settings_defaults(&settings);
	settings.scheduling_mode = TASK_SCHEDULING_DYNAMIC;
	BLI_task_parallel_range(0, edit->totpoint, &iter_data, foreach_mouse_hit_key_iter, &settings);
}

static void foreach_selected_point(PEData *data, ForPointFunc func)
{
	PTCacheEdit *edit = data->edit;
	POINT_P;

	LOOP_SELECTED_POINTS {
		func(data, p);
	}
}

static void foreach_selected_key(PEData *data, ForKeyFunc func)
{
	PTCacheEdit *edit = data->edit;
	POINT_P; KEY_K;

	LOOP_VISIBLE_POINTS {
		LOOP_SELECTED_KEYS {
			func(data, p, k, true);
		}
	}
}

static void foreach_point(PEData *data, ForPointFunc func)
{
	PTCacheEdit *edit = data->edit;
	POINT_P;

	LOOP_POINTS {
		func(data, p);
	}
}

static int count_selected_keys(Scene *scene, PTCacheEdit *edit)
{
	ParticleEditSettings *pset = PE_settings(scene);
	POINT_P; KEY_K;
	int sel = 0;

	LOOP_VISIBLE_POINTS {
		if (pset->selectmode == SCE_SELECT_POINT) {
			LOOP_SELECTED_KEYS {
				sel++;
			}
		}
		else if (pset->selectmode == SCE_SELECT_END) {
			if (point->totkey) {
				key = point->keys + point->totkey - 1;
				if (key->flag & PEK_SELECT)
					sel++;
			}
		}
	}

	return sel;
}

/************************************************/
/*			Particle Edit Mirroring				*/
/************************************************/

static void PE_update_mirror_cache(Object *ob, ParticleSystem *psys)
{
	PTCacheEdit *edit;
	ParticleSystemModifierData *psmd_eval;
	KDTree *tree;
	KDTreeNearest nearest;
	HairKey *key;
	PARTICLE_P;
	float mat[4][4], co[3];
	int index, totpart;

	edit = psys->edit;
	psmd_eval = edit->psmd_eval;
	totpart = psys->totpart;

	if (!psmd_eval->mesh_final)
		return;

	tree = BLI_kdtree_new(totpart);

	/* insert particles into kd tree */
	LOOP_PARTICLES {
		key = pa->hair;
		psys_mat_hair_to_orco(ob, psmd_eval->mesh_final, psys->part->from, pa, mat);
		copy_v3_v3(co, key->co);
		mul_m4_v3(mat, co);
		BLI_kdtree_insert(tree, p, co);
	}

	BLI_kdtree_balance(tree);

	/* lookup particles and set in mirror cache */
	if (!edit->mirror_cache)
		edit->mirror_cache = MEM_callocN(sizeof(int) * totpart, "PE mirror cache");

	LOOP_PARTICLES {
		key = pa->hair;
		psys_mat_hair_to_orco(ob, psmd_eval->mesh_final, psys->part->from, pa, mat);
		copy_v3_v3(co, key->co);
		mul_m4_v3(mat, co);
		co[0] = -co[0];

		index = BLI_kdtree_find_nearest(tree, co, &nearest);

		/* this needs a custom threshold still, duplicated for editmode mirror */
		if (index != -1 && index != p && (nearest.dist <= 0.0002f))
			edit->mirror_cache[p] = index;
		else
			edit->mirror_cache[p] = -1;
	}

	/* make sure mirrors are in two directions */
	LOOP_PARTICLES {
		if (edit->mirror_cache[p]) {
			index = edit->mirror_cache[p];
			if (edit->mirror_cache[index] != p)
				edit->mirror_cache[p] = -1;
		}
	}

	BLI_kdtree_free(tree);
}

static void PE_mirror_particle(Object *ob, Mesh *mesh, ParticleSystem *psys, ParticleData *pa, ParticleData *mpa)
{
	HairKey *hkey, *mhkey;
	PTCacheEditPoint *point, *mpoint;
	PTCacheEditKey *key, *mkey;
	PTCacheEdit *edit;
	float mat[4][4], mmat[4][4], immat[4][4];
	int i, mi, k;

	edit = psys->edit;
	i = pa - psys->particles;

	/* find mirrored particle if needed */
	if (!mpa) {
		if (!edit->mirror_cache)
			PE_update_mirror_cache(ob, psys);

		if (!edit->mirror_cache)
			return; /* something went wrong! */

		mi = edit->mirror_cache[i];
		if (mi == -1)
			return;
		mpa = psys->particles + mi;
	}
	else
		mi = mpa - psys->particles;

	point = edit->points + i;
	mpoint = edit->points + mi;

	/* make sure they have the same amount of keys */
	if (pa->totkey != mpa->totkey) {
		if (mpa->hair) MEM_freeN(mpa->hair);
		if (mpoint->keys) MEM_freeN(mpoint->keys);

		mpa->hair = MEM_dupallocN(pa->hair);
		mpa->totkey = pa->totkey;
		mpoint->keys = MEM_dupallocN(point->keys);
		mpoint->totkey = point->totkey;

		mhkey = mpa->hair;
		mkey = mpoint->keys;
		for (k = 0; k < mpa->totkey; k++, mkey++, mhkey++) {
			mkey->co = mhkey->co;
			mkey->time = &mhkey->time;
			mkey->flag &= ~PEK_SELECT;
		}
	}

	/* mirror positions and tags */
	psys_mat_hair_to_orco(ob, mesh, psys->part->from, pa, mat);
	psys_mat_hair_to_orco(ob, mesh, psys->part->from, mpa, mmat);
	invert_m4_m4(immat, mmat);

	hkey = pa->hair;
	mhkey = mpa->hair;
	key = point->keys;
	mkey = mpoint->keys;
	for (k = 0; k < pa->totkey; k++, hkey++, mhkey++, key++, mkey++) {
		copy_v3_v3(mhkey->co, hkey->co);
		mul_m4_v3(mat, mhkey->co);
		mhkey->co[0] = -mhkey->co[0];
		mul_m4_v3(immat, mhkey->co);

		if (key->flag & PEK_TAG)
			mkey->flag |= PEK_TAG;

		mkey->length = key->length;
	}

	if (point->flag & PEP_TAG)
		mpoint->flag |= PEP_TAG;
	if (point->flag & PEP_EDIT_RECALC)
		mpoint->flag |= PEP_EDIT_RECALC;
}

static void PE_apply_mirror(Object *ob, ParticleSystem *psys)
{
	PTCacheEdit *edit;
	ParticleSystemModifierData *psmd_eval;
	POINT_P;

	if (!psys)
		return;

	edit = psys->edit;
	psmd_eval = edit->psmd_eval;

	if (!psmd_eval->mesh_final)
		return;

	if (!edit->mirror_cache)
		PE_update_mirror_cache(ob, psys);

	if (!edit->mirror_cache)
		return; /* something went wrong */

	/* we delay settings the PARS_EDIT_RECALC for mirrored particles
	 * to avoid doing mirror twice */
	LOOP_POINTS {
		if (point->flag & PEP_EDIT_RECALC) {
			PE_mirror_particle(ob, psmd_eval->mesh_final, psys, psys->particles + p, NULL);

			if (edit->mirror_cache[p] != -1)
				edit->points[edit->mirror_cache[p]].flag &= ~PEP_EDIT_RECALC;
		}
	}

	LOOP_POINTS {
		if (point->flag & PEP_EDIT_RECALC)
			if (edit->mirror_cache[p] != -1)
				edit->points[edit->mirror_cache[p]].flag |= PEP_EDIT_RECALC;
	}
}

/************************************************/
/*			Edit Calculation					*/
/************************************************/

typedef struct DeflectEmitterIter {
	Object *object;
	ParticleSystem *psys;
	PTCacheEdit *edit;
	float dist;
	float emitterdist;
} DeflectEmitterIter;

static void deflect_emitter_iter(
        void *__restrict iter_data_v,
        const int iter,
        const ParallelRangeTLS *__restrict UNUSED(tls))
{
	DeflectEmitterIter *iter_data = (DeflectEmitterIter *)iter_data_v;
	PTCacheEdit *edit = iter_data->edit;
	PTCacheEditPoint *point = &edit->points[iter];
	if ((point->flag & PEP_EDIT_RECALC) == 0) {
		return;
	}
	Object *object = iter_data->object;
	ParticleSystem *psys = iter_data->psys;
	ParticleSystemModifierData *psmd_eval = iter_data->edit->psmd_eval;
	PTCacheEditKey *key;
	int k;
	float hairimat[4][4], hairmat[4][4];
	int index;
	float *vec, *nor, dvec[3], dot, dist_1st = 0.0f;
	const float dist = iter_data->dist;
	const float emitterdist = iter_data->emitterdist;
	psys_mat_hair_to_object(object,
	                        psmd_eval->mesh_final,
	                        psys->part->from,
	                        psys->particles + iter,
	                        hairmat);

	LOOP_KEYS {
		mul_m4_v3(hairmat, key->co);
	}

	LOOP_KEYS {
		if (k == 0) {
			dist_1st = len_v3v3((key + 1)->co, key->co);
			dist_1st *= dist * emitterdist;
		}
		else {
			index = BLI_kdtree_find_nearest(edit->emitter_field, key->co, NULL);

			vec = edit->emitter_cosnos + index * 6;
			nor = vec + 3;

			sub_v3_v3v3(dvec, key->co, vec);

			dot = dot_v3v3(dvec, nor);
			copy_v3_v3(dvec, nor);

			if (dot > 0.0f) {
				if (dot < dist_1st) {
					normalize_v3(dvec);
					mul_v3_fl(dvec, dist_1st - dot);
					add_v3_v3(key->co, dvec);
				}
			}
			else {
				normalize_v3(dvec);
				mul_v3_fl(dvec, dist_1st - dot);
				add_v3_v3(key->co, dvec);
			}
			if (k == 1) {
				dist_1st *= 1.3333f;
			}
		}
	}

	invert_m4_m4(hairimat, hairmat);

	LOOP_KEYS {
		mul_m4_v3(hairimat, key->co);
	}
}

/* tries to stop edited particles from going through the emitter's surface */
static void pe_deflect_emitter(Scene *scene, Object *ob, PTCacheEdit *edit)
{
	ParticleEditSettings *pset = PE_settings(scene);
	ParticleSystem *psys;
	const float dist = ED_view3d_select_dist_px() * 0.01f;

	if (edit == NULL || edit->psys == NULL ||
	    (pset->flag & PE_DEFLECT_EMITTER) == 0 ||
	    (edit->psys->flag & PSYS_GLOBAL_HAIR))
	{
		return;
	}

	psys = edit->psys;

	if (!edit->psmd_eval->mesh_final) {
		return;
	}

	DeflectEmitterIter iter_data;
	iter_data.object = ob;
	iter_data.psys = psys;
	iter_data.edit = edit;
	iter_data.dist = dist;
	iter_data.emitterdist = pset->emitterdist;

	ParallelRangeSettings settings;
	BLI_parallel_range_settings_defaults(&settings);
	settings.scheduling_mode = TASK_SCHEDULING_DYNAMIC;
	BLI_task_parallel_range(0, edit->totpoint, &iter_data, deflect_emitter_iter, &settings);
}

typedef struct ApplyLengthsIterData {
	PTCacheEdit *edit;
} ApplyLengthsIterData;

static void apply_lengths_iter(
        void *__restrict iter_data_v,
        const int iter,
        const ParallelRangeTLS *__restrict UNUSED(tls))
{
	ApplyLengthsIterData *iter_data = (ApplyLengthsIterData *)iter_data_v;
	PTCacheEdit *edit = iter_data->edit;
	PTCacheEditPoint *point = &edit->points[iter];
	if ((point->flag & PEP_EDIT_RECALC) == 0) {
		return;
	}
	PTCacheEditKey *key;
	int k;
	LOOP_KEYS {
		if (k) {
			float dv1[3];
			sub_v3_v3v3(dv1, key->co, (key - 1)->co);
			normalize_v3(dv1);
			mul_v3_fl(dv1, (key - 1)->length);
			add_v3_v3v3(key->co, (key - 1)->co, dv1);
		}
	}
}

/* force set distances between neighboring keys */
static void PE_apply_lengths(Scene *scene, PTCacheEdit *edit)
{
	ParticleEditSettings *pset = PE_settings(scene);

	if (edit == 0 || (pset->flag & PE_KEEP_LENGTHS) == 0)
		return;

	if (edit->psys && edit->psys->flag & PSYS_GLOBAL_HAIR)
		return;

	ApplyLengthsIterData iter_data;
	iter_data.edit = edit;

	ParallelRangeSettings settings;
	BLI_parallel_range_settings_defaults(&settings);
	settings.scheduling_mode = TASK_SCHEDULING_DYNAMIC;
	BLI_task_parallel_range(0, edit->totpoint, &iter_data, apply_lengths_iter, &settings);
}

typedef struct IterateLengthsIterData {
	PTCacheEdit *edit;
	ParticleEditSettings *pset;
} IterateLengthsIterData;

static void iterate_lengths_iter(
        void *__restrict iter_data_v,
        const int iter,
        const ParallelRangeTLS *__restrict UNUSED(tls))
{
	IterateLengthsIterData *iter_data = (IterateLengthsIterData *)iter_data_v;
	PTCacheEdit *edit = iter_data->edit;
	PTCacheEditPoint *point = &edit->points[iter];
	if ((point->flag & PEP_EDIT_RECALC) == 0) {
		return;
	}
	ParticleEditSettings *pset = iter_data->pset;
	float tlen;
	float dv0[3] = {0.0f, 0.0f, 0.0f};
	float dv1[3] = {0.0f, 0.0f, 0.0f};
	float dv2[3] = {0.0f, 0.0f, 0.0f};
	for (int j = 1; j < point->totkey; j++) {
		PTCacheEditKey *key;
		int k;
		float mul = 1.0f / (float)point->totkey;
		if (pset->flag & PE_LOCK_FIRST) {
			key = point->keys + 1;
			k = 1;
			dv1[0] = dv1[1] = dv1[2] = 0.0;
		}
		else {
			key = point->keys;
			k = 0;
			dv0[0] = dv0[1] = dv0[2] = 0.0;
		}

		for (; k < point->totkey; k++, key++) {
			if (k) {
				sub_v3_v3v3(dv0, (key - 1)->co, key->co);
				tlen = normalize_v3(dv0);
				mul_v3_fl(dv0, (mul * (tlen - (key - 1)->length)));
			}
			if (k < point->totkey - 1) {
				sub_v3_v3v3(dv2, (key + 1)->co, key->co);
				tlen = normalize_v3(dv2);
				mul_v3_fl(dv2, mul * (tlen - key->length));
			}
			if (k) {
				add_v3_v3((key - 1)->co, dv1);
			}
			add_v3_v3v3(dv1, dv0, dv2);
		}
	}
}

/* try to find a nice solution to keep distances between neighboring keys */
static void pe_iterate_lengths(Scene *scene, PTCacheEdit *edit)
{
	ParticleEditSettings *pset = PE_settings(scene);
	if (edit == 0 || (pset->flag & PE_KEEP_LENGTHS) == 0) {
		return;
	}
	if (edit->psys && edit->psys->flag & PSYS_GLOBAL_HAIR) {
		return;
	}

	IterateLengthsIterData iter_data;
	iter_data.edit = edit;
	iter_data.pset = pset;

	ParallelRangeSettings settings;
	BLI_parallel_range_settings_defaults(&settings);
	settings.scheduling_mode = TASK_SCHEDULING_DYNAMIC;
	BLI_task_parallel_range(0, edit->totpoint, &iter_data, iterate_lengths_iter, &settings);
}

/* set current distances to be kept between neighbouting keys */
void recalc_lengths(PTCacheEdit *edit)
{
	POINT_P; KEY_K;

	if (edit == 0)
		return;

	LOOP_EDITED_POINTS {
		key = point->keys;
		for (k = 0; k < point->totkey - 1; k++, key++) {
			key->length = len_v3v3(key->co, (key + 1)->co);
		}
	}
}

/* calculate a tree for finding nearest emitter's vertice */
void recalc_emitter_field(Depsgraph *UNUSED(depsgraph), Object *UNUSED(ob), ParticleSystem *psys)
{
	PTCacheEdit *edit = psys->edit;
	Mesh *mesh = edit->psmd_eval->mesh_final;
	float *vec, *nor;
	int i, totface /*, totvert*/;

	if (!mesh)
		return;

	if (edit->emitter_cosnos)
		MEM_freeN(edit->emitter_cosnos);

	BLI_kdtree_free(edit->emitter_field);

	totface = mesh->totface;
	/*totvert=dm->getNumVerts(dm);*/ /*UNUSED*/

	edit->emitter_cosnos = MEM_callocN(totface * 6 * sizeof(float), "emitter cosnos");

	edit->emitter_field = BLI_kdtree_new(totface);

	vec = edit->emitter_cosnos;
	nor = vec + 3;

	for (i = 0; i < totface; i++, vec += 6, nor += 6) {
		MFace *mface = &mesh->mface[i];
		MVert *mvert;

		mvert = &mesh->mvert[mface->v1];
		copy_v3_v3(vec, mvert->co);
		VECCOPY(nor, mvert->no);

		mvert = &mesh->mvert[mface->v2];
		add_v3_v3v3(vec, vec, mvert->co);
		VECADD(nor, nor, mvert->no);

		mvert = &mesh->mvert[mface->v3];
		add_v3_v3v3(vec, vec, mvert->co);
		VECADD(nor, nor, mvert->no);

		if (mface->v4) {
			mvert = &mesh->mvert[mface->v4];
			add_v3_v3v3(vec, vec, mvert->co);
			VECADD(nor, nor, mvert->no);

			mul_v3_fl(vec, 0.25);
		}
		else
			mul_v3_fl(vec, 1.0f / 3.0f);

		normalize_v3(nor);

		BLI_kdtree_insert(edit->emitter_field, i, vec);
	}

	BLI_kdtree_balance(edit->emitter_field);
}

static void PE_update_selection(Depsgraph *depsgraph, Scene *scene, Object *ob, int useflag)
{
	PTCacheEdit *edit = PE_get_current(scene, ob);
	HairKey *hkey;
	POINT_P; KEY_K;

	/* flag all particles to be updated if not using flag */
	if (!useflag)
		LOOP_POINTS {
			point->flag |= PEP_EDIT_RECALC;
		}

	/* flush edit key flag to hair key flag to preserve selection
	 * on save */
	if (edit->psys) {
		LOOP_POINTS {
			hkey = edit->psys->particles[p].hair;
			LOOP_KEYS {
				hkey->editflag = key->flag;
				hkey++;
			}
		}
	}

	psys_cache_edit_paths(depsgraph, scene, ob, edit, CFRA, G.is_rendering);


	/* disable update flag */
	LOOP_POINTS {
		point->flag &= ~PEP_EDIT_RECALC;
	}

	DEG_id_tag_update(&ob->id, ID_RECALC_SELECT);
}

void update_world_cos(Depsgraph *UNUSED(depsgraph), Object *ob, PTCacheEdit *edit)
{
	ParticleSystem *psys = edit->psys;
	ParticleSystemModifierData *psmd_eval = edit->psmd_eval;
	POINT_P; KEY_K;
	float hairmat[4][4];

	if (psys == 0 || psys->edit == 0 || psmd_eval->mesh_final == NULL)
		return;

	LOOP_POINTS {
		if (!(psys->flag & PSYS_GLOBAL_HAIR))
			psys_mat_hair_to_global(ob, psmd_eval->mesh_final, psys->part->from, psys->particles + p, hairmat);

		LOOP_KEYS {
			copy_v3_v3(key->world_co, key->co);
			if (!(psys->flag & PSYS_GLOBAL_HAIR))
				mul_m4_v3(hairmat, key->world_co);
		}
	}
}
static void update_velocities(PTCacheEdit *edit)
{
	/*TODO: get frs_sec properly */
	float vec1[3], vec2[3], frs_sec, dfra;
	POINT_P; KEY_K;

	/* hair doesn't use velocities */
	if (edit->psys || !edit->points || !edit->points->keys->vel)
		return;

	frs_sec = edit->pid.flag & PTCACHE_VEL_PER_SEC ? 25.0f : 1.0f;

	LOOP_EDITED_POINTS {
		LOOP_KEYS {
			if (k == 0) {
				dfra = *(key + 1)->time - *key->time;

				if (dfra <= 0.0f)
					continue;

				sub_v3_v3v3(key->vel, (key + 1)->co, key->co);

				if (point->totkey > 2) {
					sub_v3_v3v3(vec1, (key + 1)->co, (key + 2)->co);
					project_v3_v3v3(vec2, vec1, key->vel);
					sub_v3_v3v3(vec2, vec1, vec2);
					madd_v3_v3fl(key->vel, vec2, 0.5f);
				}
			}
			else if (k == point->totkey - 1) {
				dfra = *key->time - *(key - 1)->time;

				if (dfra <= 0.0f)
					continue;

				sub_v3_v3v3(key->vel, key->co, (key - 1)->co);

				if (point->totkey > 2) {
					sub_v3_v3v3(vec1, (key - 2)->co, (key - 1)->co);
					project_v3_v3v3(vec2, vec1, key->vel);
					sub_v3_v3v3(vec2, vec1, vec2);
					madd_v3_v3fl(key->vel, vec2, 0.5f);
				}
			}
			else {
				dfra = *(key + 1)->time - *(key - 1)->time;

				if (dfra <= 0.0f)
					continue;

				sub_v3_v3v3(key->vel, (key + 1)->co, (key - 1)->co);
			}
			mul_v3_fl(key->vel, frs_sec / dfra);
		}
	}
}

void PE_update_object(Depsgraph *depsgraph, Scene *scene, Object *ob, int useflag)
{
	/* use this to do partial particle updates, not usable when adding or
	 * removing, then a full redo is necessary and calling this may crash */
	ParticleEditSettings *pset = PE_settings(scene);
	PTCacheEdit *edit = PE_get_current(scene, ob);
	POINT_P;

	if (!edit)
		return;

	/* flag all particles to be updated if not using flag */
	if (!useflag)
		LOOP_POINTS {
			point->flag |= PEP_EDIT_RECALC;
		}

		/* do post process on particle edit keys */
		pe_iterate_lengths(scene, edit);
	pe_deflect_emitter(scene, ob, edit);
	PE_apply_lengths(scene, edit);
	if (pe_x_mirror(ob))
		PE_apply_mirror(ob, edit->psys);
	if (edit->psys)
		update_world_cos(depsgraph, ob, edit);
	if (pset->flag & PE_AUTO_VELOCITY)
		update_velocities(edit);
	PE_hide_keys_time(scene, edit, CFRA);

	/* regenerate path caches */
	psys_cache_edit_paths(depsgraph, scene, ob, edit, CFRA, G.is_rendering);

	/* disable update flag */
	LOOP_POINTS {
		point->flag &= ~PEP_EDIT_RECALC;
	}

	if (edit->psys)
		edit->psys->flag &= ~PSYS_HAIR_UPDATED;
}

/************************************************/
/*			Edit Selections						*/
/************************************************/

/*-----selection callbacks-----*/

static void select_key(PEData *data, int point_index, int key_index, bool UNUSED(is_inside))
{
	PTCacheEdit *edit = data->edit;
	PTCacheEditPoint *point = edit->points + point_index;
	PTCacheEditKey *key = point->keys + key_index;

	if (data->select)
		key->flag |= PEK_SELECT;
	else
		key->flag &= ~PEK_SELECT;

	point->flag |= PEP_EDIT_RECALC;
}

static void select_key_op(PEData *data, int point_index, int key_index, bool is_inside)
{
	PTCacheEdit *edit = data->edit;
	PTCacheEditPoint *point = edit->points + point_index;
	PTCacheEditKey *key = point->keys + key_index;
	const bool is_select = key->flag & PEK_SELECT;
	const int sel_op_result = ED_select_op_action_deselected(data->sel_op, is_select, is_inside);
	if (sel_op_result != -1) {
		SET_FLAG_FROM_TEST(key->flag, sel_op_result, PEK_SELECT);
		point->flag |= PEP_EDIT_RECALC;
	}
}

static void select_keys(PEData *data, int point_index, int UNUSED(key_index), bool UNUSED(is_inside))
{
	PTCacheEdit *edit = data->edit;
	PTCacheEditPoint *point = edit->points + point_index;
	KEY_K;

	LOOP_KEYS {
		if (data->select)
			key->flag |= PEK_SELECT;
		else
			key->flag &= ~PEK_SELECT;
	}

	point->flag |= PEP_EDIT_RECALC;
}

static void extend_key_select(PEData *data, int point_index, int key_index, bool UNUSED(is_inside))
{
	PTCacheEdit *edit = data->edit;
	PTCacheEditPoint *point = edit->points + point_index;
	PTCacheEditKey *key = point->keys + key_index;

	key->flag |= PEK_SELECT;
	point->flag |= PEP_EDIT_RECALC;
}

static void deselect_key_select(PEData *data, int point_index, int key_index, bool UNUSED(is_inside))
{
	PTCacheEdit *edit = data->edit;
	PTCacheEditPoint *point = edit->points + point_index;
	PTCacheEditKey *key = point->keys + key_index;

	key->flag &= ~PEK_SELECT;
	point->flag |= PEP_EDIT_RECALC;
}

static void toggle_key_select(PEData *data, int point_index, int key_index, bool UNUSED(is_inside))
{
	PTCacheEdit *edit = data->edit;
	PTCacheEditPoint *point = edit->points + point_index;
	PTCacheEditKey *key = point->keys + key_index;

	key->flag ^= PEK_SELECT;
	point->flag |= PEP_EDIT_RECALC;
}

/************************ de select all operator ************************/

static void select_action_apply(PTCacheEditPoint *point, PTCacheEditKey *key, int action)
{
	switch (action) {
		case SEL_SELECT:
			if ((key->flag & PEK_SELECT) == 0) {
				key->flag |= PEK_SELECT;
				point->flag |= PEP_EDIT_RECALC;
			}
			break;
		case SEL_DESELECT:
			if (key->flag & PEK_SELECT) {
				key->flag &= ~PEK_SELECT;
				point->flag |= PEP_EDIT_RECALC;
			}
			break;
		case SEL_INVERT:
			if ((key->flag & PEK_SELECT) == 0) {
				key->flag |= PEK_SELECT;
				point->flag |= PEP_EDIT_RECALC;
			}
			else {
				key->flag &= ~PEK_SELECT;
				point->flag |= PEP_EDIT_RECALC;
			}
			break;
	}
}

static int pe_select_all_exec(bContext *C, wmOperator *op)
{
	Scene *scene = CTX_data_scene(C);
	Depsgraph *depsgraph = CTX_data_depsgraph(C);
	Object *ob = CTX_data_active_object(C);
	PTCacheEdit *edit = PE_get_current(scene, ob);
	POINT_P; KEY_K;
	int action = RNA_enum_get(op->ptr, "action");

	if (action == SEL_TOGGLE) {
		action = SEL_SELECT;
		LOOP_VISIBLE_POINTS {
			LOOP_SELECTED_KEYS {
				action = SEL_DESELECT;
				break;
			}

			if (action == SEL_DESELECT)
				break;
		}
	}

	LOOP_VISIBLE_POINTS {
		LOOP_VISIBLE_KEYS {
			select_action_apply(point, key, action);
		}
	}

	PE_update_selection(depsgraph, scene, ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_select_all(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "(De)select All";
	ot->idname = "PARTICLE_OT_select_all";
	ot->description = "(De)select all particles' keys";

	/* api callbacks */
	ot->exec = pe_select_all_exec;
	ot->poll = PE_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

	WM_operator_properties_select_all(ot);
}

/************************ pick select operator ************************/

int PE_mouse_particles(bContext *C, const int mval[2], bool extend, bool deselect, bool toggle)
{
	PEData data;
	Scene *scene = CTX_data_scene(C);
	Object *ob = CTX_data_active_object(C);
	PTCacheEdit *edit = PE_get_current(scene, ob);
	POINT_P; KEY_K;

	if (!PE_start_edit(edit))
		return OPERATOR_CANCELLED;

	if (!extend && !deselect && !toggle) {
		LOOP_VISIBLE_POINTS {
			LOOP_SELECTED_KEYS {
				key->flag &= ~PEK_SELECT;
				point->flag |= PEP_EDIT_RECALC;
			}
		}
	}

	PE_set_view3d_data(C, &data);
	data.mval = mval;
	data.rad = ED_view3d_select_dist_px();

	/* 1 = nearest only */
	if (extend) {
		for_mouse_hit_keys(&data, extend_key_select, PSEL_NEAREST);
	}
	else if (deselect) {
		for_mouse_hit_keys(&data, deselect_key_select, PSEL_NEAREST);
	}
	else {
		for_mouse_hit_keys(&data, toggle_key_select, PSEL_NEAREST);
	}

	PE_update_selection(data.depsgraph, scene, ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, data.ob);

	return OPERATOR_FINISHED;
}

/************************ select root operator ************************/

static void select_root(PEData *data, int point_index)
{
	PTCacheEditPoint *point = data->edit->points + point_index;
	PTCacheEditKey *key = point->keys;

	if (point->flag & PEP_HIDE)
		return;

	if (data->select_action != SEL_TOGGLE)
		select_action_apply(point, key, data->select_action);
	else if (key->flag & PEK_SELECT)
		data->select_toggle_action = SEL_DESELECT;
}

static int select_roots_exec(bContext *C, wmOperator *op)
{
	PEData data;
	int action = RNA_enum_get(op->ptr, "action");

	PE_set_data(C, &data);

	if (action == SEL_TOGGLE) {
		data.select_action = SEL_TOGGLE;
		data.select_toggle_action = SEL_SELECT;

		foreach_point(&data, select_root);

		action = data.select_toggle_action;
	}

	data.select_action = action;
	foreach_point(&data, select_root);

	PE_update_selection(data.depsgraph, data.scene, data.ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, data.ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_select_roots(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Select Roots";
	ot->idname = "PARTICLE_OT_select_roots";
	ot->description = "Select roots of all visible particles";

	/* api callbacks */
	ot->exec = select_roots_exec;
	ot->poll = PE_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

	/* properties */
	WM_operator_properties_select_action(ot, SEL_SELECT);
}

/************************ select tip operator ************************/

static void select_tip(PEData *data, int point_index)
{
	PTCacheEditPoint *point = data->edit->points + point_index;
	PTCacheEditKey *key;

	if (point->totkey == 0) {
		return;
	}

	key = &point->keys[point->totkey - 1];

	if (point->flag & PEP_HIDE)
		return;

	if (data->select_action != SEL_TOGGLE)
		select_action_apply(point, key, data->select_action);
	else if (key->flag & PEK_SELECT)
		data->select_toggle_action = SEL_DESELECT;
}

static int select_tips_exec(bContext *C, wmOperator *op)
{
	PEData data;
	int action = RNA_enum_get(op->ptr, "action");

	PE_set_data(C, &data);

	if (action == SEL_TOGGLE) {
		data.select_action = SEL_TOGGLE;
		data.select_toggle_action = SEL_SELECT;

		foreach_point(&data, select_tip);

		action = data.select_toggle_action;
	}

	data.select_action = action;
	foreach_point(&data, select_tip);

	PE_update_selection(data.depsgraph, data.scene, data.ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, data.ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_select_tips(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Select Tips";
	ot->idname = "PARTICLE_OT_select_tips";
	ot->description = "Select tips of all visible particles";

	/* api callbacks */
	ot->exec = select_tips_exec;
	ot->poll = PE_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

	/* properties */
	WM_operator_properties_select_action(ot, SEL_SELECT);
}

/*********************** select random operator ************************/

enum { RAN_HAIR, RAN_POINTS };

static const EnumPropertyItem select_random_type_items[] = {
	{RAN_HAIR, "HAIR", 0, "Hair", ""},
	{RAN_POINTS, "POINTS", 0, "Points", ""},
	{0, NULL, 0, NULL, NULL}
};

static int select_random_exec(bContext *C, wmOperator *op)
{
	PEData data;
	int type;

	/* used by LOOP_VISIBLE_POINTS, LOOP_VISIBLE_KEYS and LOOP_KEYS */
	PTCacheEdit *edit;
	PTCacheEditPoint *point;
	PTCacheEditKey *key;
	int p;
	int k;

	const float randfac = RNA_float_get(op->ptr, "percent") / 100.0f;
	const int seed = WM_operator_properties_select_random_seed_increment_get(op);
	const bool select = (RNA_enum_get(op->ptr, "action") == SEL_SELECT);
	RNG *rng;

	type = RNA_enum_get(op->ptr, "type");

	PE_set_data(C, &data);
	data.select_action = SEL_SELECT;
	edit = PE_get_current(data.scene, data.ob);

	rng = BLI_rng_new_srandom(seed);

	switch (type) {
		case RAN_HAIR:
			LOOP_VISIBLE_POINTS {
				int flag = ((BLI_rng_get_float(rng) < randfac) == select) ? SEL_SELECT : SEL_DESELECT;
				LOOP_KEYS {
					select_action_apply(point, key, flag);
				}
			}
			break;
		case RAN_POINTS:
			LOOP_VISIBLE_POINTS {
				LOOP_VISIBLE_KEYS {
					int flag = ((BLI_rng_get_float(rng) < randfac) == select) ? SEL_SELECT : SEL_DESELECT;
					select_action_apply(point, key, flag);
				}
			}
			break;
	}

	BLI_rng_free(rng);

	PE_update_selection(data.depsgraph, data.scene, data.ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, data.ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_select_random(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Select Random";
	ot->idname = "PARTICLE_OT_select_random";
	ot->description = "Select a randomly distributed set of hair or points";

	/* api callbacks */
	ot->exec = select_random_exec;
	ot->poll = PE_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

	/* properties */
	WM_operator_properties_select_random(ot);
	ot->prop = RNA_def_enum(ot->srna, "type", select_random_type_items, RAN_HAIR,
	                        "Type", "Select either hair or points");
}

/************************ select linked operator ************************/

static int select_linked_exec(bContext *C, wmOperator *op)
{
	PEData data;
	int mval[2];
	int location[2];

	RNA_int_get_array(op->ptr, "location", location);
	mval[0] = location[0];
	mval[1] = location[1];

	PE_set_view3d_data(C, &data);
	data.mval = mval;
	data.rad = 75.0f;
	data.select = !RNA_boolean_get(op->ptr, "deselect");

	for_mouse_hit_keys(&data, select_keys, PSEL_NEAREST);
	PE_update_selection(data.depsgraph, data.scene, data.ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, data.ob);

	return OPERATOR_FINISHED;
}

static int select_linked_invoke(bContext *C, wmOperator *op, const wmEvent *event)
{
	RNA_int_set_array(op->ptr, "location", event->mval);
	return select_linked_exec(C, op);
}

void PARTICLE_OT_select_linked(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Select Linked";
	ot->idname = "PARTICLE_OT_select_linked";
	ot->description = "Select nearest particle from mouse pointer";

	/* api callbacks */
	ot->exec = select_linked_exec;
	ot->invoke = select_linked_invoke;
	ot->poll = PE_poll_view3d;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

	/* properties */
	RNA_def_boolean(ot->srna, "deselect", 0, "Deselect", "Deselect linked keys rather than selecting them");
	RNA_def_int_vector(ot->srna, "location", 2, NULL, 0, INT_MAX, "Location", "", 0, 16384);
}

/************************ box select operator ************************/
void PE_deselect_all_visible(PTCacheEdit *edit)
{
	POINT_P; KEY_K;

	LOOP_VISIBLE_POINTS {
		LOOP_SELECTED_KEYS {
			key->flag &= ~PEK_SELECT;
			point->flag |= PEP_EDIT_RECALC;
		}
	}
}

int PE_box_select(bContext *C, const rcti *rect, const int sel_op)
{
	Scene *scene = CTX_data_scene(C);
	Object *ob = CTX_data_active_object(C);
	PTCacheEdit *edit = PE_get_current(scene, ob);
	PEData data;

	if (!PE_start_edit(edit))
		return OPERATOR_CANCELLED;

	if (SEL_OP_USE_PRE_DESELECT(sel_op)) {
		PE_deselect_all_visible(edit);
	}

	PE_set_view3d_data(C, &data);
	data.rect = rect;
	data.sel_op = sel_op;

	for_mouse_hit_keys(&data, select_key_op, PSEL_ALL_KEYS);

	PE_update_selection(data.depsgraph, scene, ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, ob);

	return OPERATOR_FINISHED;
}

/************************ circle select operator ************************/

int PE_circle_select(bContext *C, int selecting, const int mval[2], float rad)
{
	Scene *scene = CTX_data_scene(C);
	Object *ob = CTX_data_active_object(C);
	PTCacheEdit *edit = PE_get_current(scene, ob);
	PEData data;

	if (!PE_start_edit(edit))
		return OPERATOR_FINISHED;

	PE_set_view3d_data(C, &data);
	data.mval = mval;
	data.rad = rad;
	data.select = selecting;

	for_mouse_hit_keys(&data, select_key, 0);

	PE_update_selection(data.depsgraph, scene, ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, ob);

	return OPERATOR_FINISHED;
}

/************************ lasso select operator ************************/

int PE_lasso_select(bContext *C, const int mcords[][2], const short moves, const int sel_op)
{
	Scene *scene = CTX_data_scene(C);
	Object *ob = CTX_data_active_object(C);
	ARegion *ar = CTX_wm_region(C);
	ParticleEditSettings *pset = PE_settings(scene);
	PTCacheEdit *edit = PE_get_current(scene, ob);
	ParticleSystem *psys = edit->psys;
	ParticleSystemModifierData *psmd_eval = edit->psmd_eval;
	POINT_P; KEY_K;
	float co[3], mat[4][4];
	int screen_co[2];

	PEData data;

	unit_m4(mat);

	if (!PE_start_edit(edit))
		return OPERATOR_CANCELLED;

	if (SEL_OP_USE_PRE_DESELECT(sel_op)) {
		PE_deselect_all_visible(edit);
	}

	/* only for depths */
	PE_set_view3d_data(C, &data);

	LOOP_VISIBLE_POINTS {
		if (edit->psys && !(psys->flag & PSYS_GLOBAL_HAIR))
			psys_mat_hair_to_global(ob, psmd_eval->mesh_final, psys->part->from, psys->particles + p, mat);

		if (pset->selectmode == SCE_SELECT_POINT) {
			LOOP_KEYS {
				copy_v3_v3(co, key->co);
				mul_m4_v3(mat, co);
				const bool is_select = key->flag & PEK_SELECT;
				const bool is_inside = (
				        (ED_view3d_project_int_global(ar, co, screen_co, V3D_PROJ_TEST_CLIP_WIN) == V3D_PROJ_RET_OK) &&
				        BLI_lasso_is_point_inside(mcords, moves, screen_co[0], screen_co[1], IS_CLIPPED) &&
				        key_test_depth(&data, co, screen_co));
				const int sel_op_result = ED_select_op_action_deselected(sel_op, is_select, is_inside);
				if (sel_op_result != -1) {
					SET_FLAG_FROM_TEST(key->flag, sel_op_result, PEK_SELECT);
					point->flag |= PEP_EDIT_RECALC;
				}
			}
		}
		else if (pset->selectmode == SCE_SELECT_END) {
			if (point->totkey) {
				key = point->keys + point->totkey - 1;
				copy_v3_v3(co, key->co);
				mul_m4_v3(mat, co);
				const bool is_select = key->flag & PEK_SELECT;
				const bool is_inside = (
				        (ED_view3d_project_int_global(ar, co, screen_co, V3D_PROJ_TEST_CLIP_WIN) == V3D_PROJ_RET_OK) &&
				        BLI_lasso_is_point_inside(mcords, moves, screen_co[0], screen_co[1], IS_CLIPPED) &&
				        key_test_depth(&data, co, screen_co));
				const int sel_op_result = ED_select_op_action_deselected(sel_op, is_select, is_inside);
				if (sel_op_result != -1) {
					SET_FLAG_FROM_TEST(key->flag, sel_op_result, PEK_SELECT);
					point->flag |= PEP_EDIT_RECALC;
				}
			}
		}
	}

	PE_update_selection(data.depsgraph, scene, ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, ob);

	return OPERATOR_FINISHED;
}

/*************************** hide operator **************************/

static int hide_exec(bContext *C, wmOperator *op)
{
	Object *ob = CTX_data_active_object(C);
	Scene *scene = CTX_data_scene(C);
	Depsgraph *depsgraph = CTX_data_depsgraph(C);

	PTCacheEdit *edit = PE_get_current(scene, ob);
	POINT_P; KEY_K;


	if (RNA_enum_get(op->ptr, "unselected")) {
		LOOP_UNSELECTED_POINTS {
			point->flag |= PEP_HIDE;
			point->flag |= PEP_EDIT_RECALC;

			LOOP_KEYS {
				key->flag &= ~PEK_SELECT;
			}
		}
	}
	else {
		LOOP_SELECTED_POINTS {
			point->flag |= PEP_HIDE;
			point->flag |= PEP_EDIT_RECALC;

			LOOP_KEYS {
				key->flag &= ~PEK_SELECT;
			}
		}
	}

	PE_update_selection(depsgraph, scene, ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_hide(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Hide Selected";
	ot->idname = "PARTICLE_OT_hide";
	ot->description = "Hide selected particles";

	/* api callbacks */
	ot->exec = hide_exec;
	ot->poll = PE_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

	/* props */
	RNA_def_boolean(ot->srna, "unselected", 0, "Unselected", "Hide unselected rather than selected");
}

/*************************** reveal operator **************************/

static int reveal_exec(bContext *C, wmOperator *op)
{
	Object *ob = CTX_data_active_object(C);
	Scene *scene = CTX_data_scene(C);
	Depsgraph *depsgraph = CTX_data_depsgraph(C);
	PTCacheEdit *edit = PE_get_current(scene, ob);
	const bool select = RNA_boolean_get(op->ptr, "select");
	POINT_P; KEY_K;

	LOOP_POINTS {
		if (point->flag & PEP_HIDE) {
			point->flag &= ~PEP_HIDE;
			point->flag |= PEP_EDIT_RECALC;

			LOOP_KEYS {
				SET_FLAG_FROM_TEST(key->flag, select, PEK_SELECT);
			}
		}
	}

	PE_update_selection(depsgraph, scene, ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_reveal(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Reveal";
	ot->idname = "PARTICLE_OT_reveal";
	ot->description = "Show hidden particles";

	/* api callbacks */
	ot->exec = reveal_exec;
	ot->poll = PE_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

	/* props */
	RNA_def_boolean(ot->srna, "select", true, "Select", "");
}

/************************ select less operator ************************/

static void select_less_keys(PEData *data, int point_index)
{
	PTCacheEdit *edit = data->edit;
	PTCacheEditPoint *point = edit->points + point_index;
	KEY_K;

	LOOP_SELECTED_KEYS {
		if (k == 0) {
			if (((key + 1)->flag & PEK_SELECT) == 0)
				key->flag |= PEK_TAG;
		}
		else if (k == point->totkey - 1) {
			if (((key - 1)->flag & PEK_SELECT) == 0)
				key->flag |= PEK_TAG;
		}
		else {
			if ((((key - 1)->flag & (key + 1)->flag) & PEK_SELECT) == 0)
				key->flag |= PEK_TAG;
		}
	}

	LOOP_KEYS {
		if (key->flag & PEK_TAG) {
			key->flag &= ~(PEK_TAG | PEK_SELECT);
			point->flag |= PEP_EDIT_RECALC; /* redraw selection only */
		}
	}
}

static int select_less_exec(bContext *C, wmOperator *UNUSED(op))
{
	PEData data;

	PE_set_data(C, &data);
	foreach_point(&data, select_less_keys);

	PE_update_selection(data.depsgraph, data.scene, data.ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, data.ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_select_less(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Select Less";
	ot->idname = "PARTICLE_OT_select_less";
	ot->description = "Deselect boundary selected keys of each particle";

	/* api callbacks */
	ot->exec = select_less_exec;
	ot->poll = PE_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/************************ select more operator ************************/

static void select_more_keys(PEData *data, int point_index)
{
	PTCacheEdit *edit = data->edit;
	PTCacheEditPoint *point = edit->points + point_index;
	KEY_K;

	LOOP_KEYS {
		if (key->flag & PEK_SELECT) continue;

		if (k == 0) {
			if ((key + 1)->flag & PEK_SELECT)
				key->flag |= PEK_TAG;
		}
		else if (k == point->totkey - 1) {
			if ((key - 1)->flag & PEK_SELECT)
				key->flag |= PEK_TAG;
		}
		else {
			if (((key - 1)->flag | (key + 1)->flag) & PEK_SELECT)
				key->flag |= PEK_TAG;
		}
	}

	LOOP_KEYS {
		if (key->flag & PEK_TAG) {
			key->flag &= ~PEK_TAG;
			key->flag |= PEK_SELECT;
			point->flag |= PEP_EDIT_RECALC; /* redraw selection only */
		}
	}
}

static int select_more_exec(bContext *C, wmOperator *UNUSED(op))
{
	PEData data;

	PE_set_data(C, &data);
	foreach_point(&data, select_more_keys);

	PE_update_selection(data.depsgraph, data.scene, data.ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_SELECTED, data.ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_select_more(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Select More";
	ot->idname = "PARTICLE_OT_select_more";
	ot->description = "Select keys linked to boundary selected keys of each particle";

	/* api callbacks */
	ot->exec = select_more_exec;
	ot->poll = PE_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/************************ rekey operator ************************/

static void rekey_particle(PEData *data, int pa_index)
{
	PTCacheEdit *edit = data->edit;
	ParticleSystem *psys = edit->psys;
	ParticleSimulationData sim = {0};
	ParticleData *pa = psys->particles + pa_index;
	PTCacheEditPoint *point = edit->points + pa_index;
	ParticleKey state;
	HairKey *key, *new_keys, *okey;
	PTCacheEditKey *ekey;
	float dval, sta, end;
	int k;

	sim.depsgraph = data->depsgraph;
	sim.scene = data->scene;
	sim.ob = data->ob;
	sim.psys = edit->psys;

	pa->flag |= PARS_REKEY;

	key = new_keys = MEM_callocN(data->totrekey * sizeof(HairKey), "Hair re-key keys");

	okey = pa->hair;
	/* root and tip stay the same */
	copy_v3_v3(key->co, okey->co);
	copy_v3_v3((key + data->totrekey - 1)->co, (okey + pa->totkey - 1)->co);

	sta = key->time = okey->time;
	end = (key + data->totrekey - 1)->time = (okey + pa->totkey - 1)->time;
	dval = (end - sta) / (float)(data->totrekey - 1);

	/* interpolate new keys from old ones */
	for (k = 1, key++; k < data->totrekey - 1; k++, key++) {
		state.time = (float)k / (float)(data->totrekey - 1);
		psys_get_particle_on_path(&sim, pa_index, &state, 0);
		copy_v3_v3(key->co, state.co);
		key->time = sta + k * dval;
	}

	/* replace keys */
	if (pa->hair)
		MEM_freeN(pa->hair);
	pa->hair = new_keys;

	point->totkey = pa->totkey = data->totrekey;


	if (point->keys)
		MEM_freeN(point->keys);
	ekey = point->keys = MEM_callocN(pa->totkey * sizeof(PTCacheEditKey), "Hair re-key edit keys");

	for (k = 0, key = pa->hair; k < pa->totkey; k++, key++, ekey++) {
		ekey->co = key->co;
		ekey->time = &key->time;
		ekey->flag |= PEK_SELECT;
		if (!(psys->flag & PSYS_GLOBAL_HAIR))
			ekey->flag |= PEK_USE_WCO;
	}

	pa->flag &= ~PARS_REKEY;
	point->flag |= PEP_EDIT_RECALC;
}

static int rekey_exec(bContext *C, wmOperator *op)
{
	PEData data;

	PE_set_data(C, &data);

	data.dval = 1.0f / (float)(data.totrekey - 1);
	data.totrekey = RNA_int_get(op->ptr, "keys_number");

	foreach_selected_point(&data, rekey_particle);

	recalc_lengths(data.edit);
	PE_update_object(data.depsgraph, data.scene, data.ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_EDITED, data.ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_rekey(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Rekey";
	ot->idname = "PARTICLE_OT_rekey";
	ot->description = "Change the number of keys of selected particles (root and tip keys included)";

	/* api callbacks */
	ot->exec = rekey_exec;
	ot->invoke = WM_operator_props_popup;
	ot->poll = PE_hair_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

	/* properties */
	RNA_def_int(ot->srna, "keys_number", 2, 2, INT_MAX, "Number of Keys", "", 2, 100);
}

static void rekey_particle_to_time(const bContext *C, Scene *scene, Object *ob, int pa_index, float path_time)
{
	PTCacheEdit *edit = PE_get_current(scene, ob);
	ParticleSystem *psys;
	ParticleSimulationData sim = {0};
	ParticleData *pa;
	ParticleKey state;
	HairKey *new_keys, *key;
	PTCacheEditKey *ekey;
	int k;

	if (!edit || !edit->psys) return;

	psys = edit->psys;

	sim.depsgraph = CTX_data_depsgraph(C);
	sim.scene = scene;
	sim.ob = ob;
	sim.psys = psys;

	pa = psys->particles + pa_index;

	pa->flag |= PARS_REKEY;

	key = new_keys = MEM_dupallocN(pa->hair);

	/* interpolate new keys from old ones (roots stay the same) */
	for (k = 1, key++; k < pa->totkey; k++, key++) {
		state.time = path_time * (float)k / (float)(pa->totkey - 1);
		psys_get_particle_on_path(&sim, pa_index, &state, 0);
		copy_v3_v3(key->co, state.co);
	}

	/* replace hair keys */
	if (pa->hair)
		MEM_freeN(pa->hair);
	pa->hair = new_keys;

	/* update edit pointers */
	for (k = 0, key = pa->hair, ekey = edit->points[pa_index].keys; k < pa->totkey; k++, key++, ekey++) {
		ekey->co = key->co;
		ekey->time = &key->time;
	}

	pa->flag &= ~PARS_REKEY;
}

/************************* utilities **************************/

static int remove_tagged_particles(Object *ob, ParticleSystem *psys, int mirror)
{
	PTCacheEdit *edit = psys->edit;
	ParticleData *pa, *npa = 0, *new_pars = 0;
	POINT_P;
	PTCacheEditPoint *npoint = 0, *new_points = 0;
	ParticleSystemModifierData *psmd_eval;
	int i, new_totpart = psys->totpart, removed = 0;

	if (mirror) {
		/* mirror tags */
		psmd_eval = edit->psmd_eval;

		LOOP_TAGGED_POINTS {
			PE_mirror_particle(ob, psmd_eval->mesh_final, psys, psys->particles + p, NULL);
		}
	}

	LOOP_TAGGED_POINTS {
		new_totpart--;
		removed++;
	}

	if (new_totpart != psys->totpart) {
		if (new_totpart) {
			npa = new_pars = MEM_callocN(new_totpart * sizeof(ParticleData), "ParticleData array");
			npoint = new_points = MEM_callocN(new_totpart * sizeof(PTCacheEditPoint), "PTCacheEditKey array");

			if (ELEM(NULL, new_pars, new_points)) {
				/* allocation error! */
				if (new_pars)
					MEM_freeN(new_pars);
				if (new_points)
					MEM_freeN(new_points);
				return 0;
			}
		}

		pa = psys->particles;
		point = edit->points;
		for (i = 0; i < psys->totpart; i++, pa++, point++) {
			if (point->flag & PEP_TAG) {
				if (point->keys)
					MEM_freeN(point->keys);
				if (pa->hair)
					MEM_freeN(pa->hair);
			}
			else {
				memcpy(npa, pa, sizeof(ParticleData));
				memcpy(npoint, point, sizeof(PTCacheEditPoint));
				npa++;
				npoint++;
			}
		}

		if (psys->particles) MEM_freeN(psys->particles);
		psys->particles = new_pars;

		if (edit->points) MEM_freeN(edit->points);
		edit->points = new_points;

		if (edit->mirror_cache) {
			MEM_freeN(edit->mirror_cache);
			edit->mirror_cache = NULL;
		}

		if (psys->child) {
			MEM_freeN(psys->child);
			psys->child = NULL;
			psys->totchild = 0;
		}

		edit->totpoint = psys->totpart = new_totpart;
	}

	return removed;
}

static void remove_tagged_keys(Object *ob, ParticleSystem *psys)
{
	PTCacheEdit *edit = psys->edit;
	ParticleData *pa;
	HairKey *hkey, *nhkey, *new_hkeys = 0;
	POINT_P; KEY_K;
	PTCacheEditKey *nkey, *new_keys;
	ParticleSystemModifierData *psmd_eval;
	short new_totkey;

	if (pe_x_mirror(ob)) {
		/* mirror key tags */
		psmd_eval = psys_get_modifier(ob, psys);

		LOOP_POINTS {
			LOOP_TAGGED_KEYS {
				PE_mirror_particle(ob, psmd_eval->mesh_final, psys, psys->particles + p, NULL);
				break;
			}
		}
	}

	LOOP_POINTS {
		new_totkey = point->totkey;
		LOOP_TAGGED_KEYS {
			new_totkey--;
		}
		/* we can't have elements with less than two keys*/
		if (new_totkey < 2)
			point->flag |= PEP_TAG;
	}
	remove_tagged_particles(ob, psys, pe_x_mirror(ob));

	LOOP_POINTS {
		pa = psys->particles + p;
		new_totkey = pa->totkey;

		LOOP_TAGGED_KEYS {
			new_totkey--;
		}

		if (new_totkey != pa->totkey) {
			nhkey = new_hkeys = MEM_callocN(new_totkey * sizeof(HairKey), "HairKeys");
			nkey = new_keys = MEM_callocN(new_totkey * sizeof(PTCacheEditKey), "particle edit keys");

			hkey = pa->hair;
			LOOP_KEYS {
				while (key->flag & PEK_TAG && hkey < pa->hair + pa->totkey) {
					key++;
					hkey++;
				}

				if (hkey < pa->hair + pa->totkey) {
					copy_v3_v3(nhkey->co, hkey->co);
					nhkey->editflag = hkey->editflag;
					nhkey->time = hkey->time;
					nhkey->weight = hkey->weight;

					nkey->co = nhkey->co;
					nkey->time = &nhkey->time;
					/* these can be copied from old edit keys */
					nkey->flag = key->flag;
					nkey->ftime = key->ftime;
					nkey->length = key->length;
					copy_v3_v3(nkey->world_co, key->world_co);
				}
				nkey++;
				nhkey++;
				hkey++;
			}

			if (pa->hair)
				MEM_freeN(pa->hair);

			if (point->keys)
				MEM_freeN(point->keys);

			pa->hair = new_hkeys;
			point->keys = new_keys;

			point->totkey = pa->totkey = new_totkey;

			/* flag for recalculating length */
			point->flag |= PEP_EDIT_RECALC;
		}
	}
}

/************************ subdivide opertor *********************/

/* works like normal edit mode subdivide, inserts keys between neighboring selected keys */
static void subdivide_particle(PEData *data, int pa_index)
{
	PTCacheEdit *edit = data->edit;
	ParticleSystem *psys = edit->psys;
	ParticleSimulationData sim = {0};
	ParticleData *pa = psys->particles + pa_index;
	PTCacheEditPoint *point = edit->points + pa_index;
	ParticleKey state;
	HairKey *key, *nkey, *new_keys;
	PTCacheEditKey *ekey, *nekey, *new_ekeys;

	int k;
	short totnewkey = 0;
	float endtime;

	sim.depsgraph = data->depsgraph;
	sim.scene = data->scene;
	sim.ob = data->ob;
	sim.psys = edit->psys;

	for (k = 0, ekey = point->keys; k < pa->totkey - 1; k++, ekey++) {
		if (ekey->flag & PEK_SELECT && (ekey + 1)->flag & PEK_SELECT)
			totnewkey++;
	}

	if (totnewkey == 0) return;

	pa->flag |= PARS_REKEY;

	nkey = new_keys = MEM_callocN((pa->totkey + totnewkey) * (sizeof(HairKey)), "Hair subdivide keys");
	nekey = new_ekeys = MEM_callocN((pa->totkey + totnewkey) * (sizeof(PTCacheEditKey)), "Hair subdivide edit keys");

	key = pa->hair;
	endtime = key[pa->totkey - 1].time;

	for (k = 0, ekey = point->keys; k < pa->totkey - 1; k++, key++, ekey++) {

		memcpy(nkey, key, sizeof(HairKey));
		memcpy(nekey, ekey, sizeof(PTCacheEditKey));

		nekey->co = nkey->co;
		nekey->time = &nkey->time;

		nkey++;
		nekey++;

		if (ekey->flag & PEK_SELECT && (ekey + 1)->flag & PEK_SELECT) {
			nkey->time = (key->time + (key + 1)->time) * 0.5f;
			state.time = (endtime != 0.0f) ? nkey->time / endtime : 0.0f;
			psys_get_particle_on_path(&sim, pa_index, &state, 0);
			copy_v3_v3(nkey->co, state.co);

			nekey->co = nkey->co;
			nekey->time = &nkey->time;
			nekey->flag |= PEK_SELECT;
			if (!(psys->flag & PSYS_GLOBAL_HAIR))
				nekey->flag |= PEK_USE_WCO;

			nekey++;
			nkey++;
		}
	}
	/*tip still not copied*/
	memcpy(nkey, key, sizeof(HairKey));
	memcpy(nekey, ekey, sizeof(PTCacheEditKey));

	nekey->co = nkey->co;
	nekey->time = &nkey->time;

	if (pa->hair)
		MEM_freeN(pa->hair);
	pa->hair = new_keys;

	if (point->keys)
		MEM_freeN(point->keys);
	point->keys = new_ekeys;

	point->totkey = pa->totkey = pa->totkey + totnewkey;
	point->flag |= PEP_EDIT_RECALC;
	pa->flag &= ~PARS_REKEY;
}

static int subdivide_exec(bContext *C, wmOperator *UNUSED(op))
{
	PEData data;

	PE_set_data(C, &data);
	foreach_point(&data, subdivide_particle);

	recalc_lengths(data.edit);
	PE_update_object(data.depsgraph, data.scene, data.ob, 1);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_EDITED, data.ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_subdivide(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Subdivide";
	ot->idname = "PARTICLE_OT_subdivide";
	ot->description = "Subdivide selected particles segments (adds keys)";

	/* api callbacks */
	ot->exec = subdivide_exec;
	ot->poll = PE_hair_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/************************ remove doubles opertor *********************/

static int remove_doubles_exec(bContext *C, wmOperator *op)
{
	Scene *scene = CTX_data_scene(C);
	Object *ob = CTX_data_active_object(C);
	PTCacheEdit *edit = PE_get_current(scene, ob);
	ParticleSystem *psys = edit->psys;
	ParticleSystemModifierData *psmd_eval;
	KDTree *tree;
	KDTreeNearest nearest[10];
	POINT_P;
	float mat[4][4], co[3], threshold = RNA_float_get(op->ptr, "threshold");
	int n, totn, removed, totremoved;

	if (psys->flag & PSYS_GLOBAL_HAIR)
		return OPERATOR_CANCELLED;

	edit = psys->edit;
	psmd_eval = edit->psmd_eval;
	totremoved = 0;

	do {
		removed = 0;

		tree = BLI_kdtree_new(psys->totpart);

		/* insert particles into kd tree */
		LOOP_SELECTED_POINTS {
			psys_mat_hair_to_object(ob, psmd_eval->mesh_final, psys->part->from, psys->particles + p, mat);
			copy_v3_v3(co, point->keys->co);
			mul_m4_v3(mat, co);
			BLI_kdtree_insert(tree, p, co);
		}

		BLI_kdtree_balance(tree);

		/* tag particles to be removed */
		LOOP_SELECTED_POINTS {
			psys_mat_hair_to_object(ob, psmd_eval->mesh_final, psys->part->from, psys->particles + p, mat);
			copy_v3_v3(co, point->keys->co);
			mul_m4_v3(mat, co);

			totn = BLI_kdtree_find_nearest_n(tree, co, nearest, 10);

			for (n = 0; n < totn; n++) {
				/* this needs a custom threshold still */
				if (nearest[n].index > p && nearest[n].dist < threshold) {
					if (!(point->flag & PEP_TAG)) {
						point->flag |= PEP_TAG;
						removed++;
					}
				}
			}
		}

		BLI_kdtree_free(tree);

		/* remove tagged particles - don't do mirror here! */
		remove_tagged_particles(ob, psys, 0);
		totremoved += removed;
	} while (removed);

	if (totremoved == 0)
		return OPERATOR_CANCELLED;

	BKE_reportf(op->reports, RPT_INFO, "Removed %d double particles", totremoved);

	DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_EDITED, ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_remove_doubles(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Remove Doubles";
	ot->idname = "PARTICLE_OT_remove_doubles";
	ot->description = "Remove selected particles close enough of others";

	/* api callbacks */
	ot->exec = remove_doubles_exec;
	ot->poll = PE_hair_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

	/* properties */
	RNA_def_float(ot->srna, "threshold", 0.0002f, 0.0f, FLT_MAX,
	              "Merge Distance", "Threshold distance within which particles are removed", 0.00001f, 0.1f);
}


static int weight_set_exec(bContext *C, wmOperator *op)
{
	Scene *scene = CTX_data_scene(C);
	ParticleEditSettings *pset = PE_settings(scene);
	Object *ob = CTX_data_active_object(C);
	PTCacheEdit *edit = PE_get_current(scene, ob);
	ParticleSystem *psys = edit->psys;
	POINT_P;
	KEY_K;
	HairKey *hkey;
	float weight;
	ParticleBrushData *brush = &pset->brush[pset->brushtype];
	float factor = RNA_float_get(op->ptr, "factor");

	weight = brush->strength;
	edit = psys->edit;

	LOOP_SELECTED_POINTS {
		ParticleData *pa = psys->particles + p;

		LOOP_SELECTED_KEYS {
			hkey = pa->hair + k;
			hkey->weight = interpf(weight, hkey->weight, factor);
		}
	}

	DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_EDITED, ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_weight_set(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Weight Set";
	ot->idname = "PARTICLE_OT_weight_set";
	ot->description = "Set the weight of selected keys";

	/* api callbacks */
	ot->exec = weight_set_exec;
	ot->poll = PE_hair_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

	RNA_def_float(ot->srna, "factor", 1, 0, 1, "Factor",
	              "Interpolation factor between current brush weight, and keys' weights", 0, 1);
}

/************************ cursor drawing *******************************/

static void brush_drawcursor(bContext *C, int x, int y, void *UNUSED(customdata))
{
	Scene *scene = CTX_data_scene(C);
	ParticleEditSettings *pset = PE_settings(scene);
	ParticleBrushData *brush;

	if (pset->brushtype < 0) {
		return;
	}

	brush = &pset->brush[pset->brushtype];

	if (brush) {
		uint pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
		immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);

		immUniformColor4ub(255, 255, 255, 128);

		GPU_line_smooth(true);
		GPU_blend(true);

		imm_draw_circle_wire_2d(pos, (float)x, (float)y, pe_brush_size_get(scene, brush), 40);

		GPU_blend(false);
		GPU_line_smooth(false);

		immUnbindProgram();
	}
}

static void toggle_particle_cursor(bContext *C, int enable)
{
	ParticleEditSettings *pset = PE_settings(CTX_data_scene(C));

	if (pset->paintcursor && !enable) {
		WM_paint_cursor_end(CTX_wm_manager(C), pset->paintcursor);
		pset->paintcursor = NULL;
	}
	else if (enable)
		pset->paintcursor = WM_paint_cursor_activate(
		        CTX_wm_manager(C),
		        SPACE_VIEW3D, RGN_TYPE_WINDOW,
		        PE_poll_view3d,
		        brush_drawcursor,
		        NULL);
}

/*************************** delete operator **************************/

enum { DEL_PARTICLE, DEL_KEY };

static const EnumPropertyItem delete_type_items[] = {
	{DEL_PARTICLE, "PARTICLE", 0, "Particle", ""},
	{DEL_KEY, "KEY", 0, "Key", ""},
	{0, NULL, 0, NULL, NULL}
};

static void set_delete_particle(PEData *data, int pa_index)
{
	PTCacheEdit *edit = data->edit;

	edit->points[pa_index].flag |= PEP_TAG;
}

static void set_delete_particle_key(PEData *data, int pa_index, int key_index, bool UNUSED(is_inside))
{
	PTCacheEdit *edit = data->edit;

	edit->points[pa_index].keys[key_index].flag |= PEK_TAG;
}

static int delete_exec(bContext *C, wmOperator *op)
{
	PEData data;
	int type = RNA_enum_get(op->ptr, "type");

	PE_set_data(C, &data);

	if (type == DEL_KEY) {
		foreach_selected_key(&data, set_delete_particle_key);
		remove_tagged_keys(data.ob, data.edit->psys);
		recalc_lengths(data.edit);
	}
	else if (type == DEL_PARTICLE) {
		foreach_selected_point(&data, set_delete_particle);
		remove_tagged_particles(data.ob, data.edit->psys, pe_x_mirror(data.ob));
		recalc_lengths(data.edit);
	}

	DEG_id_tag_update(&data.ob->id, ID_RECALC_GEOMETRY);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_EDITED, data.ob);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_delete(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Delete";
	ot->idname = "PARTICLE_OT_delete";
	ot->description = "Delete selected particles or keys";

	/* api callbacks */
	ot->exec = delete_exec;
	ot->invoke = WM_menu_invoke;
	ot->poll = PE_hair_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

	/* properties */
	ot->prop = RNA_def_enum(ot->srna, "type", delete_type_items, DEL_PARTICLE, "Type", "Delete a full particle or only keys");
}

/*************************** mirror operator **************************/

static void PE_mirror_x(
        Scene *scene, Object *ob, int tagged)
{
	Mesh *me = (Mesh *)(ob->data);
	ParticleSystemModifierData *psmd_eval;
	PTCacheEdit *edit = PE_get_current(scene, ob);
	ParticleSystem *psys = edit->psys;
	ParticleData *pa, *newpa, *new_pars;
	PTCacheEditPoint *newpoint, *new_points;
	POINT_P; KEY_K;
	HairKey *hkey;
	int *mirrorfaces = NULL;
	int rotation, totpart, newtotpart;

	if (psys->flag & PSYS_GLOBAL_HAIR)
		return;

	psmd_eval = edit->psmd_eval;
	if (!psmd_eval->mesh_final)
		return;

	const bool use_dm_final_indices = (psys->part->use_modifier_stack && !psmd_eval->mesh_final->runtime.deformed_only);

	/* NOTE: this is not nice to use tessfaces but hard to avoid since pa->num uses tessfaces */
	BKE_mesh_tessface_ensure(me);

	/* Note: In case psys uses Mesh tessface indices, we mirror final Mesh itself, not orig mesh. Avoids an (impossible)
	 *       mesh -> orig -> mesh tessface indices conversion... */
	mirrorfaces = mesh_get_x_mirror_faces(ob, NULL, use_dm_final_indices ? psmd_eval->mesh_final : NULL);

	if (!edit->mirror_cache)
		PE_update_mirror_cache(ob, psys);

	totpart = psys->totpart;
	newtotpart = psys->totpart;
	LOOP_VISIBLE_POINTS {
		pa = psys->particles + p;

		if (!tagged) {
			if (point_is_selected(point)) {
				if (edit->mirror_cache[p] != -1) {
					/* already has a mirror, don't need to duplicate */
					PE_mirror_particle(ob, psmd_eval->mesh_final, psys, pa, NULL);
					continue;
				}
				else
					point->flag |= PEP_TAG;
			}
		}

		if ((point->flag & PEP_TAG) && mirrorfaces[pa->num * 2] != -1)
			newtotpart++;
	}

	if (newtotpart != psys->totpart) {
		MFace *mtessface = use_dm_final_indices ? psmd_eval->mesh_final->mface : me->mface;

		/* allocate new arrays and copy existing */
		new_pars = MEM_callocN(newtotpart * sizeof(ParticleData), "ParticleData new");
		new_points = MEM_callocN(newtotpart * sizeof(PTCacheEditPoint), "PTCacheEditPoint new");

		if (psys->particles) {
			memcpy(new_pars, psys->particles, totpart * sizeof(ParticleData));
			MEM_freeN(psys->particles);
		}
		psys->particles = new_pars;

		if (edit->points) {
			memcpy(new_points, edit->points, totpart * sizeof(PTCacheEditPoint));
			MEM_freeN(edit->points);
		}
		edit->points = new_points;

		if (edit->mirror_cache) {
			MEM_freeN(edit->mirror_cache);
			edit->mirror_cache = NULL;
		}

		edit->totpoint = psys->totpart = newtotpart;

		/* create new elements */
		newpa = psys->particles + totpart;
		newpoint = edit->points + totpart;

		for (p = 0, point = edit->points; p < totpart; p++, point++) {
			pa = psys->particles + p;
			const int pa_num = pa->num;

			if (point->flag & PEP_HIDE)
				continue;

			if (!(point->flag & PEP_TAG) || mirrorfaces[pa_num * 2] == -1)
				continue;

			/* duplicate */
			*newpa = *pa;
			*newpoint = *point;
			if (pa->hair) newpa->hair = MEM_dupallocN(pa->hair);
			if (point->keys) newpoint->keys = MEM_dupallocN(point->keys);

			/* rotate weights according to vertex index rotation */
			rotation = mirrorfaces[pa_num * 2 + 1];
			newpa->fuv[0] = pa->fuv[2];
			newpa->fuv[1] = pa->fuv[1];
			newpa->fuv[2] = pa->fuv[0];
			newpa->fuv[3] = pa->fuv[3];
			while (rotation--) {
				if (mtessface[pa_num].v4) {
					SHIFT4(float, newpa->fuv[0], newpa->fuv[1], newpa->fuv[2], newpa->fuv[3]);
				}
				else {
					SHIFT3(float, newpa->fuv[0], newpa->fuv[1], newpa->fuv[2]);
				}
			}

			/* assign face index */
			/* NOTE: mesh_get_x_mirror_faces generates -1 for non-found mirror, same as DMCACHE_NOTFOUND... */
			newpa->num = mirrorfaces[pa_num * 2];

			if (use_dm_final_indices) {
				newpa->num_dmcache = DMCACHE_ISCHILD;
			}
			else {
				newpa->num_dmcache = psys_particle_dm_face_lookup(
				        psmd_eval->mesh_final, psmd_eval->mesh_original, newpa->num, newpa->fuv, NULL);
			}

			/* update edit key pointers */
			key = newpoint->keys;
			for (k = 0, hkey = newpa->hair; k < newpa->totkey; k++, hkey++, key++) {
				key->co = hkey->co;
				key->time = &hkey->time;
			}

			/* map key positions as mirror over x axis */
			PE_mirror_particle(ob, psmd_eval->mesh_final, psys, pa, newpa);

			newpa++;
			newpoint++;
		}
	}

	LOOP_POINTS {
		point->flag &= ~PEP_TAG;
	}

	MEM_freeN(mirrorfaces);
}

static int mirror_exec(bContext *C, wmOperator *UNUSED(op))
{
	Scene *scene = CTX_data_scene(C);
	Object *ob = CTX_data_active_object(C);
	PTCacheEdit *edit = PE_get_current(scene, ob);

	PE_mirror_x(scene, ob, 0);

	update_world_cos(CTX_data_depsgraph(C), ob, edit);
	WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_EDITED, ob);
	DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_mirror(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Mirror";
	ot->idname = "PARTICLE_OT_mirror";
	ot->description = "Duplicate and mirror the selected particles along the local X axis";

	/* api callbacks */
	ot->exec = mirror_exec;
	ot->poll = PE_hair_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/************************* brush edit callbacks ********************/

static void brush_comb(PEData *data, float UNUSED(mat[4][4]), float imat[4][4], int point_index, int key_index, PTCacheEditKey *key)
{
	ParticleEditSettings *pset = PE_settings(data->scene);
	float cvec[3], fac;

	if (pset->flag & PE_LOCK_FIRST && key_index == 0) return;

	fac = (float)pow((double)(1.0f - data->dist / data->rad), (double)data->combfac);

	copy_v3_v3(cvec, data->dvec);
	mul_mat3_m4_v3(imat, cvec);
	mul_v3_fl(cvec, fac);
	add_v3_v3(key->co, cvec);

	(data->edit->points + point_index)->flag |= PEP_EDIT_RECALC;
}

static void brush_cut(PEData *data, int pa_index)
{
	PTCacheEdit *edit = data->edit;
	ARegion *ar = data->vc.ar;
	Object *ob = data->ob;
	ParticleEditSettings *pset = PE_settings(data->scene);
	ParticleCacheKey *key = edit->pathcache[pa_index];
	float rad2, cut_time = 1.0;
	float x0, x1, v0, v1, o0, o1, xo0, xo1, d, dv;
	int k, cut, keys = (int)pow(2.0, (double)pset->draw_step);
	int screen_co[2];

	BLI_assert(data->rng != NULL);
	/* blunt scissors */
	if (BLI_rng_get_float(data->rng) > data->cutfac) {
		return;
	}

	/* don't cut hidden */
	if (edit->points[pa_index].flag & PEP_HIDE)
		return;

	if (ED_view3d_project_int_global(ar, key->co, screen_co, V3D_PROJ_TEST_CLIP_NEAR) != V3D_PROJ_RET_OK)
		return;

	rad2 = data->rad * data->rad;

	cut = 0;

	x0 = (float)screen_co[0];
	x1 = (float)screen_co[1];

	o0 = (float)data->mval[0];
	o1 = (float)data->mval[1];

	xo0 = x0 - o0;
	xo1 = x1 - o1;

	/* check if root is inside circle */
	if (xo0 * xo0 + xo1 * xo1 < rad2 && key_test_depth(data, key->co, screen_co)) {
		cut_time = -1.0f;
		cut = 1;
	}
	else {
		/* calculate path time closest to root that was inside the circle */
		for (k = 1, key++; k <= keys; k++, key++) {

			if ((ED_view3d_project_int_global(ar, key->co, screen_co, V3D_PROJ_TEST_CLIP_NEAR) != V3D_PROJ_RET_OK) ||
			    key_test_depth(data, key->co, screen_co) == 0)
			{
				x0 = (float)screen_co[0];
				x1 = (float)screen_co[1];

				xo0 = x0 - o0;
				xo1 = x1 - o1;
				continue;
			}

			v0 = (float)screen_co[0] - x0;
			v1 = (float)screen_co[1] - x1;

			dv = v0 * v0 + v1 * v1;

			d = (v0 * xo1 - v1 * xo0);

			d = dv * rad2 - d * d;

			if (d > 0.0f) {
				d = sqrtf(d);

				cut_time = -(v0 * xo0 + v1 * xo1 + d);

				if (cut_time > 0.0f) {
					cut_time /= dv;

					if (cut_time < 1.0f) {
						cut_time += (float)(k - 1);
						cut_time /= (float)keys;
						cut = 1;
						break;
					}
				}
			}

			x0 = (float)screen_co[0];
			x1 = (float)screen_co[1];

			xo0 = x0 - o0;
			xo1 = x1 - o1;
		}
	}

	if (cut) {
		if (cut_time < 0.0f) {
			edit->points[pa_index].flag |= PEP_TAG;
		}
		else {
			rekey_particle_to_time(data->context, data->scene, ob, pa_index, cut_time);
			edit->points[pa_index].flag |= PEP_EDIT_RECALC;
		}
	}
}

static void brush_length(PEData *data, int point_index)
{
	PTCacheEdit *edit = data->edit;
	PTCacheEditPoint *point = edit->points + point_index;
	KEY_K;
	float dvec[3], pvec[3] = {0.0f, 0.0f, 0.0f};

	LOOP_KEYS {
		if (k == 0) {
			copy_v3_v3(pvec, key->co);
		}
		else {
			sub_v3_v3v3(dvec, key->co, pvec);
			copy_v3_v3(pvec, key->co);
			mul_v3_fl(dvec, data->growfac);
			add_v3_v3v3(key->co, (key - 1)->co, dvec);
		}
	}

	point->flag |= PEP_EDIT_RECALC;
}

static void brush_puff(PEData *data, int point_index)
{
	PTCacheEdit *edit = data->edit;
	ParticleSystem *psys = edit->psys;
	PTCacheEditPoint *point = edit->points + point_index;
	KEY_K;
	float mat[4][4], imat[4][4];

	float onor_prev[3];  /* previous normal (particle-space) */
	float ofs_prev[3];  /* accumulate offset for puff_volume (particle-space) */
	float co_root[3], no_root[3];  /* root location and normal (global-space) */
	float co_prev[3], co[3];  /* track key coords as we loop (global-space) */
	float fac = 0.0f, length_accum = 0.0f;
	bool puff_volume = false;
	bool changed = false;

	zero_v3(ofs_prev);

	{
		ParticleEditSettings *pset = PE_settings(data->scene);
		ParticleBrushData *brush = &pset->brush[pset->brushtype];
		puff_volume = (brush->flag & PE_BRUSH_DATA_PUFF_VOLUME) != 0;
	}

	if (psys && !(psys->flag & PSYS_GLOBAL_HAIR)) {
		psys_mat_hair_to_global(data->ob, data->mesh, psys->part->from, psys->particles + point_index, mat);
		invert_m4_m4(imat, mat);
	}
	else {
		unit_m4(mat);
		unit_m4(imat);
	}

	LOOP_KEYS {
		float kco[3];

		if (k == 0) {
			/* find root coordinate and normal on emitter */
			copy_v3_v3(co, key->co);
			mul_m4_v3(mat, co);
			mul_v3_m4v3(kco, data->ob->imat, co); /* use 'kco' as the object space version of worldspace 'co', ob->imat is set before calling */

			point_index = BLI_kdtree_find_nearest(edit->emitter_field, kco, NULL);
			if (point_index == -1) return;

			copy_v3_v3(co_root, co);
			copy_v3_v3(no_root, &edit->emitter_cosnos[point_index * 6 + 3]);
			mul_mat3_m4_v3(data->ob->obmat, no_root);  /* normal into global-space */
			normalize_v3(no_root);

			if (puff_volume) {
				copy_v3_v3(onor_prev, no_root);
				mul_mat3_m4_v3(imat, onor_prev); /* global-space into particle space */
				normalize_v3(onor_prev);
			}

			fac = (float)pow((double)(1.0f - data->dist / data->rad), (double)data->pufffac);
			fac *= 0.025f;
			if (data->invert)
				fac = -fac;
		}
		else {
			/* compute position as if hair was standing up straight.
			 * */
			float length;
			copy_v3_v3(co_prev, co);
			copy_v3_v3(co, key->co);
			mul_m4_v3(mat, co);
			length = len_v3v3(co_prev, co);
			length_accum += length;

			if ((data->select == 0 || (key->flag & PEK_SELECT)) && !(key->flag & PEK_HIDE)) {
				float dco[3];  /* delta temp var */

				madd_v3_v3v3fl(kco, co_root, no_root, length_accum);

				/* blend between the current and straight position */
				sub_v3_v3v3(dco, kco, co);
				madd_v3_v3fl(co, dco, fac);
				/* keep the same distance from the root or we get glitches [#35406] */
				dist_ensure_v3_v3fl(co, co_root, length_accum);

				/* re-use dco to compare before and after translation and add to the offset  */
				copy_v3_v3(dco, key->co);

				mul_v3_m4v3(key->co, imat, co);

				if (puff_volume) {
					/* accumulate the total distance moved to apply to unselected
					 * keys that come after */
					sub_v3_v3v3(ofs_prev, key->co, dco);
				}
				changed = true;
			}
			else {

				if (puff_volume) {
#if 0
					/* this is simple but looks bad, adds annoying kinks */
					add_v3_v3(key->co, ofs);
#else
					/* translate (not rotate) the rest of the hair if its not selected  */
					{
#if 0                   /* kindof works but looks worse then what's below */

						/* Move the unselected point on a vector based on the
						 * hair direction and the offset */
						float c1[3], c2[3];
						sub_v3_v3v3(dco, lastco, co);
						mul_mat3_m4_v3(imat, dco); /* into particle space */

						/* move the point along a vector perpendicular to the
						 * hairs direction, reduces odd kinks, */
						cross_v3_v3v3(c1, ofs, dco);
						cross_v3_v3v3(c2, c1, dco);
						normalize_v3(c2);
						mul_v3_fl(c2, len_v3(ofs));
						add_v3_v3(key->co, c2);
#else
						/* Move the unselected point on a vector based on the
						 * the normal of the closest geometry */
						float oco[3], onor[3];
						copy_v3_v3(oco, key->co);
						mul_m4_v3(mat, oco);
						mul_v3_m4v3(kco, data->ob->imat, oco); /* use 'kco' as the object space version of worldspace 'co', ob->imat is set before calling */

						point_index = BLI_kdtree_find_nearest(edit->emitter_field, kco, NULL);
						if (point_index != -1) {
							copy_v3_v3(onor, &edit->emitter_cosnos[point_index * 6 + 3]);
							mul_mat3_m4_v3(data->ob->obmat, onor); /* normal into worldspace */
							mul_mat3_m4_v3(imat, onor); /* worldspace into particle space */
							normalize_v3(onor);
						}
						else {
							copy_v3_v3(onor, onor_prev);
						}

						if (!is_zero_v3(ofs_prev)) {
							mul_v3_fl(onor, len_v3(ofs_prev));

							add_v3_v3(key->co, onor);
						}

						copy_v3_v3(onor_prev, onor);
#endif
					}
#endif
				}
			}
		}
	}

	if (changed)
		point->flag |= PEP_EDIT_RECALC;
}


static void BKE_brush_weight_get(PEData *data, float UNUSED(mat[4][4]), float UNUSED(imat[4][4]), int point_index, int key_index, PTCacheEditKey *UNUSED(key))
{
	/* roots have full weight always */
	if (key_index) {
		PTCacheEdit *edit = data->edit;
		ParticleSystem *psys = edit->psys;

		ParticleData *pa = psys->particles + point_index;
		pa->hair[key_index].weight = data->weightfac;

		(data->edit->points + point_index)->flag |= PEP_EDIT_RECALC;
	}
}

static void brush_smooth_get(PEData *data, float mat[4][4], float UNUSED(imat[4][4]), int UNUSED(point_index), int key_index, PTCacheEditKey *key)
{
	if (key_index) {
		float dvec[3];

		sub_v3_v3v3(dvec, key->co, (key - 1)->co);
		mul_mat3_m4_v3(mat, dvec);
		add_v3_v3(data->vec, dvec);
		data->tot++;
	}
}

static void brush_smooth_do(PEData *data, float UNUSED(mat[4][4]), float imat[4][4], int point_index, int key_index, PTCacheEditKey *key)
{
	float vec[3], dvec[3];

	if (key_index) {
		copy_v3_v3(vec, data->vec);
		mul_mat3_m4_v3(imat, vec);

		sub_v3_v3v3(dvec, key->co, (key - 1)->co);

		sub_v3_v3v3(dvec, vec, dvec);
		mul_v3_fl(dvec, data->smoothfac);

		add_v3_v3(key->co, dvec);
	}

	(data->edit->points + point_index)->flag |= PEP_EDIT_RECALC;
}

/* convert from triangle barycentric weights to quad mean value weights */
static void intersect_dm_quad_weights(const float v1[3], const float v2[3], const float v3[3], const float v4[3], float w[4])
{
	float co[3], vert[4][3];

	copy_v3_v3(vert[0], v1);
	copy_v3_v3(vert[1], v2);
	copy_v3_v3(vert[2], v3);
	copy_v3_v3(vert[3], v4);

	co[0] = v1[0] * w[0] + v2[0] * w[1] + v3[0] * w[2] + v4[0] * w[3];
	co[1] = v1[1] * w[0] + v2[1] * w[1] + v3[1] * w[2] + v4[1] * w[3];
	co[2] = v1[2] * w[0] + v2[2] * w[1] + v3[2] * w[2] + v4[2] * w[3];

	interp_weights_poly_v3(w, vert, 4, co);
}

/** Check intersection with an evaluated mesh. */
static int particle_intersect_mesh(Depsgraph *depsgraph, Scene *UNUSED(scene), Object *ob, Mesh *mesh,
                                   float *vert_cos,
                                   const float co1[3], const float co2[3],
                                   float *min_d, int *min_face, float *min_w,
                                   float *face_minmax, float *pa_minmax,
                                   float radius, float *ipoint)
{
	MFace *mface = NULL;
	MVert *mvert = NULL;
	int i, totface, intersect = 0;
	float cur_d, cur_uv[2], v1[3], v2[3], v3[3], v4[3], min[3], max[3], p_min[3], p_max[3];
	float cur_ipoint[3];

	if (mesh == NULL) {
		psys_disable_all(ob);

		Scene *scene_eval = DEG_get_evaluated_scene(depsgraph);
		Object *ob_eval = DEG_get_evaluated_object(depsgraph, ob);

		mesh = mesh_get_eval_final(depsgraph, scene_eval, ob_eval, CD_MASK_BAREMESH);
		if (mesh == NULL) {
			mesh = mesh_get_eval_deform(depsgraph, scene_eval, ob_eval, CD_MASK_BAREMESH);
		}

		psys_enable_all(ob);

		if (mesh == NULL) {
			return 0;
		}
	}

	/* BMESH_ONLY, deform dm may not have tessface */
	BKE_mesh_tessface_ensure(mesh);


	if (pa_minmax == 0) {
		INIT_MINMAX(p_min, p_max);
		minmax_v3v3_v3(p_min, p_max, co1);
		minmax_v3v3_v3(p_min, p_max, co2);
	}
	else {
		copy_v3_v3(p_min, pa_minmax);
		copy_v3_v3(p_max, pa_minmax + 3);
	}

	totface = mesh->totface;
	mface = mesh->mface;
	mvert = mesh->mvert;

	/* lets intersect the faces */
	for (i = 0; i < totface; i++, mface++) {
		if (vert_cos) {
			copy_v3_v3(v1, vert_cos + 3 * mface->v1);
			copy_v3_v3(v2, vert_cos + 3 * mface->v2);
			copy_v3_v3(v3, vert_cos + 3 * mface->v3);
			if (mface->v4)
				copy_v3_v3(v4, vert_cos + 3 * mface->v4);
		}
		else {
			copy_v3_v3(v1, mvert[mface->v1].co);
			copy_v3_v3(v2, mvert[mface->v2].co);
			copy_v3_v3(v3, mvert[mface->v3].co);
			if (mface->v4)
				copy_v3_v3(v4, mvert[mface->v4].co);
		}

		if (face_minmax == 0) {
			INIT_MINMAX(min, max);
			DO_MINMAX(v1, min, max);
			DO_MINMAX(v2, min, max);
			DO_MINMAX(v3, min, max);
			if (mface->v4)
				DO_MINMAX(v4, min, max);
			if (isect_aabb_aabb_v3(min, max, p_min, p_max) == 0)
				continue;
		}
		else {
			copy_v3_v3(min, face_minmax + 6 * i);
			copy_v3_v3(max, face_minmax + 6 * i + 3);
			if (isect_aabb_aabb_v3(min, max, p_min, p_max) == 0)
				continue;
		}

		if (radius > 0.0f) {
			if (isect_sweeping_sphere_tri_v3(co1, co2, radius, v2, v3, v1, &cur_d, cur_ipoint)) {
				if (cur_d < *min_d) {
					*min_d = cur_d;
					copy_v3_v3(ipoint, cur_ipoint);
					*min_face = i;
					intersect = 1;
				}
			}
			if (mface->v4) {
				if (isect_sweeping_sphere_tri_v3(co1, co2, radius, v4, v1, v3, &cur_d, cur_ipoint)) {
					if (cur_d < *min_d) {
						*min_d = cur_d;
						copy_v3_v3(ipoint, cur_ipoint);
						*min_face = i;
						intersect = 1;
					}
				}
			}
		}
		else {
			if (isect_line_segment_tri_v3(co1, co2, v1, v2, v3, &cur_d, cur_uv)) {
				if (cur_d < *min_d) {
					*min_d = cur_d;
					min_w[0] = 1.0f - cur_uv[0] - cur_uv[1];
					min_w[1] = cur_uv[0];
					min_w[2] = cur_uv[1];
					min_w[3] = 0.0f;
					if (mface->v4)
						intersect_dm_quad_weights(v1, v2, v3, v4, min_w);
					*min_face = i;
					intersect = 1;
				}
			}
			if (mface->v4) {
				if (isect_line_segment_tri_v3(co1, co2, v1, v3, v4, &cur_d, cur_uv)) {
					if (cur_d < *min_d) {
						*min_d = cur_d;
						min_w[0] = 1.0f - cur_uv[0] - cur_uv[1];
						min_w[1] = 0.0f;
						min_w[2] = cur_uv[0];
						min_w[3] = cur_uv[1];
						intersect_dm_quad_weights(v1, v2, v3, v4, min_w);
						*min_face = i;
						intersect = 1;
					}
				}
			}
		}
	}
	return intersect;
}

typedef struct BrushAddCountIterData {
	Depsgraph *depsgraph;
	Scene *scene;
	Object *object;
	Mesh *mesh;
	PEData *data;
	int number;
	short size;
	float imat[4][4];
	ParticleData *add_pars;
	int num_added;
} BrushAddCountIterData;

typedef struct BrushAddCountIterTLSData {
	RNG *rng;
	int num_added;
} BrushAddCountIterTLSData;

static void brush_add_count_iter(
        void *__restrict iter_data_v,
        const int iter,
        const ParallelRangeTLS *__restrict tls_v)
{
	BrushAddCountIterData *iter_data = (BrushAddCountIterData *)iter_data_v;
	Depsgraph *depsgraph = iter_data->depsgraph;
	PEData *data = iter_data->data;
	PTCacheEdit *edit = data->edit;
	ParticleSystem *psys = edit->psys;
	ParticleSystemModifierData *psmd_eval = edit->psmd_eval;
	ParticleData *add_pars = iter_data->add_pars;
	BrushAddCountIterTLSData *tls = tls_v->userdata_chunk;
	const int number = iter_data->number;
	const short size = iter_data->size;
	const short size2 = size * size;
	float dmx, dmy;
	if (number > 1) {
		dmx = size;
		dmy = size;
		if (tls->rng == NULL) {
			tls->rng = BLI_rng_new_srandom(
			        psys->seed + data->mval[0] + data->mval[1] + tls_v->thread_id);
		}
		/* rejection sampling to get points in circle */
		while (dmx * dmx + dmy * dmy > size2) {
			dmx = (2.0f * BLI_rng_get_float(tls->rng) - 1.0f) * size;
			dmy = (2.0f * BLI_rng_get_float(tls->rng) - 1.0f) * size;
		}
	}
	else {
		dmx = 0.0f;
		dmy = 0.0f;
	}

	float mco[2];
	mco[0] = data->mval[0] + dmx;
	mco[1] = data->mval[1] + dmy;

	float co1[3], co2[3];
	ED_view3d_win_to_segment_clipped(depsgraph, data->vc.ar, data->vc.v3d, mco, co1, co2, true);

	mul_m4_v3(iter_data->imat, co1);
	mul_m4_v3(iter_data->imat, co2);
	float min_d = 2.0;

	/* warning, returns the derived mesh face */
	BLI_assert(iter_data->mesh != NULL);
	if (particle_intersect_mesh(depsgraph, iter_data->scene, iter_data->object, iter_data->mesh,
	                            0, co1, co2,
	                            &min_d,
	                            &add_pars[iter].num_dmcache,
	                            add_pars[iter].fuv,
	                            0, 0, 0, 0))
	{
		if (psys->part->use_modifier_stack && !psmd_eval->mesh_final->runtime.deformed_only) {
			add_pars[iter].num = add_pars[iter].num_dmcache;
			add_pars[iter].num_dmcache = DMCACHE_ISCHILD;
		}
		else if (iter_data->mesh == psmd_eval->mesh_original) {
			/* Final DM is not same topology as orig mesh, we have to map num_dmcache to real final dm. */
			add_pars[iter].num = add_pars[iter].num_dmcache;
			add_pars[iter].num_dmcache = psys_particle_dm_face_lookup(
			        psmd_eval->mesh_final, psmd_eval->mesh_original,
			        add_pars[iter].num, add_pars[iter].fuv, NULL);
		}
		else {
			add_pars[iter].num = add_pars[iter].num_dmcache;
		}
		if (add_pars[iter].num != DMCACHE_NOTFOUND) {
			tls->num_added++;
		}
	}
}

static void brush_add_count_iter_finalize(void *__restrict userdata_v,
                                          void *__restrict userdata_chunk_v)
{
	BrushAddCountIterData *iter_data = (BrushAddCountIterData *)userdata_v;
	BrushAddCountIterTLSData *tls = (BrushAddCountIterTLSData *)userdata_chunk_v;
	iter_data->num_added += tls->num_added;
	if (tls->rng != NULL) {
		BLI_rng_free(tls->rng);
	}
}

static int brush_add(const bContext *C, PEData *data, short number)
{
	Depsgraph *depsgraph = CTX_data_depsgraph(C);
	Scene *scene = data->scene;
	Object *ob = data->ob;
	Mesh *mesh;
	PTCacheEdit *edit = data->edit;
	ParticleSystem *psys = edit->psys;
	ParticleData *add_pars;
	ParticleSystemModifierData *psmd_eval = edit->psmd_eval;
	ParticleSimulationData sim = {0};
	ParticleEditSettings *pset = PE_settings(scene);
	int i, k, n = 0, totpart = psys->totpart;
	float co1[3], imat[4][4];
	float framestep, timestep;
	short size = pset->brush[PE_BRUSH_ADD].size;
	RNG *rng;

	invert_m4_m4(imat, ob->obmat);

	if (psys->flag & PSYS_GLOBAL_HAIR)
		return 0;

	add_pars = MEM_callocN(number * sizeof(ParticleData), "ParticleData add");

	rng = BLI_rng_new_srandom(psys->seed + data->mval[0] + data->mval[1]);

	sim.depsgraph = depsgraph;
	sim.scene = scene;
	sim.ob = ob;
	sim.psys = psys;
	sim.psmd = psmd_eval;

	timestep = psys_get_timestep(&sim);

	if (psys->part->use_modifier_stack || psmd_eval->mesh_final->runtime.deformed_only) {
		mesh = psmd_eval->mesh_final;
	}
	else {
		mesh = psmd_eval->mesh_original;
	}
	BLI_assert(mesh);

	/* Calculate positions of new particles to add, based on brush interseciton
	 * with object. New particle data is assigned to a corresponding to check
	 * index element of add_pars array. This means, that add_pars is a sparse
	 * array.
	 */
	BrushAddCountIterData iter_data;
	iter_data.depsgraph = depsgraph;
	iter_data.scene = scene;
	iter_data.object = ob;
	iter_data.mesh = mesh;
	iter_data.data = data;
	iter_data.number = number;
	iter_data.size = size;
	iter_data.add_pars = add_pars;
	iter_data.num_added = 0;
	copy_m4_m4(iter_data.imat, imat);

	BrushAddCountIterTLSData tls = {NULL};

	ParallelRangeSettings settings;
	BLI_parallel_range_settings_defaults(&settings);
	settings.scheduling_mode = TASK_SCHEDULING_DYNAMIC;
	settings.userdata_chunk = &tls;
	settings.userdata_chunk_size = sizeof(BrushAddCountIterTLSData);
	settings.func_finalize = brush_add_count_iter_finalize;
	BLI_task_parallel_range(0, number, &iter_data, brush_add_count_iter, &settings);

	/* Convert add_parse to a dense array, where all new particles are in the
	 * beginnign of the array.
	 */
	n = iter_data.num_added;
	for (int current_iter = 0, new_index = 0; current_iter < number; current_iter++) {
		if (add_pars[current_iter].num == DMCACHE_NOTFOUND) {
			continue;
		}
		if (new_index != current_iter) {
			new_index++;
			continue;
		}
		memcpy(add_pars + new_index, add_pars + current_iter, sizeof(ParticleData));
		new_index++;
	}

	/* TODO(sergey): Consider multi-threading this part as well. */
	if (n) {
		int newtotpart = totpart + n;
		float hairmat[4][4], cur_co[3];
		KDTree *tree = 0;
		ParticleData *pa, *new_pars = MEM_callocN(newtotpart * sizeof(ParticleData), "ParticleData new");
		PTCacheEditPoint *point, *new_points = MEM_callocN(newtotpart * sizeof(PTCacheEditPoint), "PTCacheEditPoint array new");
		PTCacheEditKey *key;
		HairKey *hkey;

		/* save existing elements */
		memcpy(new_pars, psys->particles, totpart * sizeof(ParticleData));
		memcpy(new_points, edit->points, totpart * sizeof(PTCacheEditPoint));

		/* change old arrays to new ones */
		if (psys->particles) MEM_freeN(psys->particles);
		psys->particles = new_pars;

		if (edit->points) MEM_freeN(edit->points);
		edit->points = new_points;

		if (edit->mirror_cache) {
			MEM_freeN(edit->mirror_cache);
			edit->mirror_cache = NULL;
		}

		/* create tree for interpolation */
		if (pset->flag & PE_INTERPOLATE_ADDED && psys->totpart) {
			tree = BLI_kdtree_new(psys->totpart);

			for (i = 0, pa = psys->particles; i < totpart; i++, pa++) {
				psys_particle_on_dm(psmd_eval->mesh_final, psys->part->from, pa->num, pa->num_dmcache, pa->fuv, pa->foffset, cur_co, 0, 0, 0, 0);
				BLI_kdtree_insert(tree, i, cur_co);
			}

			BLI_kdtree_balance(tree);
		}

		edit->totpoint = psys->totpart = newtotpart;

		/* create new elements */
		pa = psys->particles + totpart;
		point = edit->points + totpart;

		for (i = totpart; i < newtotpart; i++, pa++, point++) {
			memcpy(pa, add_pars + i - totpart, sizeof(ParticleData));
			pa->hair = MEM_callocN(pset->totaddkey * sizeof(HairKey), "BakeKey key add");
			key = point->keys = MEM_callocN(pset->totaddkey * sizeof(PTCacheEditKey), "PTCacheEditKey add");
			point->totkey = pa->totkey = pset->totaddkey;

			for (k = 0, hkey = pa->hair; k < pa->totkey; k++, hkey++, key++) {
				key->co = hkey->co;
				key->time = &hkey->time;

				if (!(psys->flag & PSYS_GLOBAL_HAIR))
					key->flag |= PEK_USE_WCO;
			}

			pa->size = 1.0f;
			initialize_particle(&sim, pa);
			reset_particle(&sim, pa, 0.0, 1.0);
			point->flag |= PEP_EDIT_RECALC;
			if (pe_x_mirror(ob))
				point->flag |= PEP_TAG; /* signal for duplicate */

			framestep = pa->lifetime / (float)(pset->totaddkey - 1);

			if (tree) {
				ParticleData *ppa;
				HairKey *thkey;
				ParticleKey key3[3];
				KDTreeNearest ptn[3];
				int w, maxw;
				float maxd, totw = 0.0, weight[3];

				psys_particle_on_dm(psmd_eval->mesh_final, psys->part->from, pa->num, pa->num_dmcache, pa->fuv, pa->foffset, co1, 0, 0, 0, 0);
				maxw = BLI_kdtree_find_nearest_n(tree, co1, ptn, 3);

				maxd = ptn[maxw - 1].dist;

				for (w = 0; w < maxw; w++) {
					weight[w] = (float)pow(2.0, (double)(-6.0f * ptn[w].dist / maxd));
					totw += weight[w];
				}
				for (; w < 3; w++) {
					weight[w] = 0.0f;
				}

				if (totw > 0.0f) {
					for (w = 0; w < maxw; w++)
						weight[w] /= totw;
				}
				else {
					for (w = 0; w < maxw; w++)
						weight[w] = 1.0f / maxw;
				}

				ppa = psys->particles + ptn[0].index;

				for (k = 0; k < pset->totaddkey; k++) {
					thkey = (HairKey *)pa->hair + k;
					thkey->time = pa->time + k * framestep;

					key3[0].time = thkey->time / 100.0f;
					psys_get_particle_on_path(&sim, ptn[0].index, key3, 0);
					mul_v3_fl(key3[0].co, weight[0]);

					/* TODO: interpolating the weight would be nicer */
					thkey->weight = (ppa->hair + MIN2(k, ppa->totkey - 1))->weight;

					if (maxw > 1) {
						key3[1].time = key3[0].time;
						psys_get_particle_on_path(&sim, ptn[1].index, &key3[1], 0);
						mul_v3_fl(key3[1].co, weight[1]);
						add_v3_v3(key3[0].co, key3[1].co);

						if (maxw > 2) {
							key3[2].time = key3[0].time;
							psys_get_particle_on_path(&sim, ptn[2].index, &key3[2], 0);
							mul_v3_fl(key3[2].co, weight[2]);
							add_v3_v3(key3[0].co, key3[2].co);
						}
					}

					if (k == 0)
						sub_v3_v3v3(co1, pa->state.co, key3[0].co);

					add_v3_v3v3(thkey->co, key3[0].co, co1);

					thkey->time = key3[0].time;
				}
			}
			else {
				for (k = 0, hkey = pa->hair; k < pset->totaddkey; k++, hkey++) {
					madd_v3_v3v3fl(hkey->co, pa->state.co, pa->state.vel, k * framestep * timestep);
					hkey->time += k * framestep;
					hkey->weight = 1.f - (float)k / (float)(pset->totaddkey - 1);
				}
			}
			for (k = 0, hkey = pa->hair; k < pset->totaddkey; k++, hkey++) {
				psys_mat_hair_to_global(ob, psmd_eval->mesh_final, psys->part->from, pa, hairmat);
				invert_m4_m4(imat, hairmat);
				mul_m4_v3(imat, hkey->co);
			}
		}

		if (tree)
			BLI_kdtree_free(tree);
	}

	MEM_freeN(add_pars);

	BLI_rng_free(rng);

	return n;
}

/************************* brush edit operator ********************/

typedef struct BrushEdit {
	Scene *scene;
	ViewLayer *view_layer;
	Object *ob;
	PTCacheEdit *edit;

	int first;
	int lastmouse[2];
	float zfac;

	/* optional cached view settings to avoid setting on every mousemove */
	PEData data;
} BrushEdit;

static int brush_edit_init(bContext *C, wmOperator *op)
{
	Scene *scene = CTX_data_scene(C);
	ViewLayer *view_layer = CTX_data_view_layer(C);
	Object *ob = CTX_data_active_object(C);
	ParticleEditSettings *pset = PE_settings(scene);
	PTCacheEdit *edit = PE_get_current(scene, ob);
	ARegion *ar = CTX_wm_region(C);
	BrushEdit *bedit;
	float min[3], max[3];

	if (pset->brushtype < 0)
		return 0;

	/* set the 'distance factor' for grabbing (used in comb etc) */
	INIT_MINMAX(min, max);
	PE_minmax(scene, view_layer, min, max);
	mid_v3_v3v3(min, min, max);

	bedit = MEM_callocN(sizeof(BrushEdit), "BrushEdit");
	bedit->first = 1;
	op->customdata = bedit;

	bedit->scene = scene;
	bedit->view_layer = view_layer;
	bedit->ob = ob;
	bedit->edit = edit;

	bedit->zfac = ED_view3d_calc_zfac(ar->regiondata, min, NULL);

	/* cache view depths and settings for re-use */
	PE_set_view3d_data(C, &bedit->data);
	PE_create_random_generator(&bedit->data);

	return 1;
}

static void brush_edit_apply(bContext *C, wmOperator *op, PointerRNA *itemptr)
{
	BrushEdit *bedit = op->customdata;
	Depsgraph *depsgraph = CTX_data_depsgraph(C);
	Scene *scene = bedit->scene;
	Object *ob = bedit->ob;
	PTCacheEdit *edit = bedit->edit;
	ParticleEditSettings *pset = PE_settings(scene);
	ParticleSystemModifierData *psmd_eval = edit->psmd_eval;
	ParticleBrushData *brush = &pset->brush[pset->brushtype];
	ARegion *ar = CTX_wm_region(C);
	float vec[3], mousef[2];
	int mval[2];
	int flip, mouse[2], removed = 0, added = 0, selected = 0, tot_steps = 1, step = 1;
	float dx, dy, dmax;
	int lock_root = pset->flag & PE_LOCK_FIRST;

	if (!PE_start_edit(edit))
		return;

	RNA_float_get_array(itemptr, "mouse", mousef);
	mouse[0] = mousef[0];
	mouse[1] = mousef[1];
	flip = RNA_boolean_get(itemptr, "pen_flip");

	if (bedit->first) {
		bedit->lastmouse[0] = mouse[0];
		bedit->lastmouse[1] = mouse[1];
	}

	dx = mouse[0] - bedit->lastmouse[0];
	dy = mouse[1] - bedit->lastmouse[1];

	mval[0] = mouse[0];
	mval[1] = mouse[1];


	/* disable locking temporatily for disconnected hair */
	if (edit->psys && edit->psys->flag & PSYS_GLOBAL_HAIR)
		pset->flag &= ~PE_LOCK_FIRST;

	if (((pset->brushtype == PE_BRUSH_ADD) ?
	     (sqrtf(dx * dx + dy * dy) > pset->brush[PE_BRUSH_ADD].step) : (dx != 0 || dy != 0)) || bedit->first)
	{
		PEData data = bedit->data;
		data.context = C; // TODO(mai): why isnt this set in bedit->data?

		view3d_operator_needs_opengl(C);
		selected = (short)count_selected_keys(scene, edit);

		dmax = max_ff(fabsf(dx), fabsf(dy));
		tot_steps = dmax / (0.2f * pe_brush_size_get(scene, brush)) + 1;

		dx /= (float)tot_steps;
		dy /= (float)tot_steps;

		for (step = 1; step <= tot_steps; step++) {
			mval[0] = bedit->lastmouse[0] + step * dx;
			mval[1] = bedit->lastmouse[1] + step * dy;

			switch (pset->brushtype) {
				case PE_BRUSH_COMB:
				{
					const float mval_f[2] = {dx, dy};
					data.mval = mval;
					data.rad = pe_brush_size_get(scene, brush);

					data.combfac = (brush->strength - 0.5f) * 2.0f;
					if (data.combfac < 0.0f)
						data.combfac = 1.0f - 9.0f * data.combfac;
					else
						data.combfac = 1.0f - data.combfac;

					invert_m4_m4(ob->imat, ob->obmat);

					ED_view3d_win_to_delta(ar, mval_f, vec, bedit->zfac);
					data.dvec = vec;

					foreach_mouse_hit_key(&data, brush_comb, selected);
					break;
				}
				case PE_BRUSH_CUT:
				{
					if (edit->psys && edit->pathcache) {
						data.mval = mval;
						data.rad = pe_brush_size_get(scene, brush);
						data.cutfac = brush->strength;

						if (selected)
							foreach_selected_point(&data, brush_cut);
						else
							foreach_point(&data, brush_cut);

						removed = remove_tagged_particles(ob, edit->psys, pe_x_mirror(ob));
						if (pset->flag & PE_KEEP_LENGTHS)
							recalc_lengths(edit);
					}
					else
						removed = 0;

					break;
				}
				case PE_BRUSH_LENGTH:
				{
					data.mval = mval;

					data.rad = pe_brush_size_get(scene, brush);
					data.growfac = brush->strength / 50.0f;

					if (brush->invert ^ flip)
						data.growfac = 1.0f - data.growfac;
					else
						data.growfac = 1.0f + data.growfac;

					foreach_mouse_hit_point(&data, brush_length, selected);

					if (pset->flag & PE_KEEP_LENGTHS)
						recalc_lengths(edit);
					break;
				}
				case PE_BRUSH_PUFF:
				{
					if (edit->psys) {
						data.mesh = psmd_eval->mesh_final;
						data.mval = mval;
						data.rad = pe_brush_size_get(scene, brush);
						data.select = selected;

						data.pufffac = (brush->strength - 0.5f) * 2.0f;
						if (data.pufffac < 0.0f)
							data.pufffac = 1.0f - 9.0f * data.pufffac;
						else
							data.pufffac = 1.0f - data.pufffac;

						data.invert = (brush->invert ^ flip);
						invert_m4_m4(ob->imat, ob->obmat);

						foreach_mouse_hit_point(&data, brush_puff, selected);
					}
					break;
				}
				case PE_BRUSH_ADD:
				{
					if (edit->psys && edit->psys->part->from == PART_FROM_FACE) {
						data.mval = mval;

						added = brush_add(C, &data, brush->count);

						if (pset->flag & PE_KEEP_LENGTHS)
							recalc_lengths(edit);
					}
					else
						added = 0;
					break;
				}
				case PE_BRUSH_SMOOTH:
				{
					data.mval = mval;
					data.rad = pe_brush_size_get(scene, brush);

					data.vec[0] = data.vec[1] = data.vec[2] = 0.0f;
					data.tot = 0;

					data.smoothfac = brush->strength;

					invert_m4_m4(ob->imat, ob->obmat);

					foreach_mouse_hit_key(&data, brush_smooth_get, selected);

					if (data.tot) {
						mul_v3_fl(data.vec, 1.0f / (float)data.tot);
						foreach_mouse_hit_key(&data, brush_smooth_do, selected);
					}

					break;
				}
				case PE_BRUSH_WEIGHT:
				{
					if (edit->psys) {
						data.mesh = psmd_eval->mesh_final;
						data.mval = mval;
						data.rad = pe_brush_size_get(scene, brush);

						data.weightfac = brush->strength; /* note that this will never be zero */

						foreach_mouse_hit_key(&data, BKE_brush_weight_get, selected);
					}

					break;
				}
			}
			if ((pset->flag & PE_KEEP_LENGTHS) == 0)
				recalc_lengths(edit);

			if (ELEM(pset->brushtype, PE_BRUSH_ADD, PE_BRUSH_CUT) && (added || removed)) {
				if (pset->brushtype == PE_BRUSH_ADD && pe_x_mirror(ob))
					PE_mirror_x(scene, ob, 1);

				update_world_cos(depsgraph, ob, edit);
				psys_free_path_cache(NULL, edit);
				DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
			}
			else {
				PE_update_object(depsgraph, scene, ob, 1);
			}
		}

		if (edit->psys) {
			WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_EDITED, ob);
			BKE_particle_batch_cache_dirty_tag(edit->psys, BKE_PARTICLE_BATCH_DIRTY_ALL);
			DEG_id_tag_update(&ob->id, ID_RECALC_SELECT);
		}
		else {
			DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
			WM_event_add_notifier(C, NC_OBJECT | ND_MODIFIER, ob);
		}

		bedit->lastmouse[0] = mouse[0];
		bedit->lastmouse[1] = mouse[1];
		bedit->first = 0;
	}

	pset->flag |= lock_root;
}

static void brush_edit_exit(wmOperator *op)
{
	BrushEdit *bedit = op->customdata;

	PE_free_random_generator(&bedit->data);
	MEM_freeN(bedit);
}

static int brush_edit_exec(bContext *C, wmOperator *op)
{
	if (!brush_edit_init(C, op))
		return OPERATOR_CANCELLED;

	RNA_BEGIN(op->ptr, itemptr, "stroke")
	{
		brush_edit_apply(C, op, &itemptr);
	}
	RNA_END;

	brush_edit_exit(op);

	return OPERATOR_FINISHED;
}

static void brush_edit_apply_event(bContext *C, wmOperator *op, const wmEvent *event)
{
	PointerRNA itemptr;
	float mouse[2];

	VECCOPY2D(mouse, event->mval);

	/* fill in stroke */
	RNA_collection_add(op->ptr, "stroke", &itemptr);

	RNA_float_set_array(&itemptr, "mouse", mouse);
	RNA_boolean_set(&itemptr, "pen_flip", event->shift != false); // XXX hardcoded

	/* apply */
	brush_edit_apply(C, op, &itemptr);
}

static int brush_edit_invoke(bContext *C, wmOperator *op, const wmEvent *event)
{
	if (!brush_edit_init(C, op))
		return OPERATOR_CANCELLED;

	brush_edit_apply_event(C, op, event);

	WM_event_add_modal_handler(C, op);

	return OPERATOR_RUNNING_MODAL;
}

static int brush_edit_modal(bContext *C, wmOperator *op, const wmEvent *event)
{
	switch (event->type) {
		case LEFTMOUSE:
		case MIDDLEMOUSE:
		case RIGHTMOUSE: // XXX hardcoded
			if (event->val == KM_RELEASE) {
				brush_edit_exit(op);
				return OPERATOR_FINISHED;
			}
			break;
		case MOUSEMOVE:
			brush_edit_apply_event(C, op, event);
			break;
	}

	return OPERATOR_RUNNING_MODAL;
}

static void brush_edit_cancel(bContext *UNUSED(C), wmOperator *op)
{
	brush_edit_exit(op);
}

void PARTICLE_OT_brush_edit(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Brush Edit";
	ot->idname = "PARTICLE_OT_brush_edit";
	ot->description = "Apply a stroke of brush to the particles";

	/* api callbacks */
	ot->exec = brush_edit_exec;
	ot->invoke = brush_edit_invoke;
	ot->modal = brush_edit_modal;
	ot->cancel = brush_edit_cancel;
	ot->poll = PE_poll_view3d;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO | OPTYPE_BLOCKING;

	/* properties */
	PropertyRNA *prop;
	prop = RNA_def_collection_runtime(ot->srna, "stroke", &RNA_OperatorStrokeElement, "Stroke", "");
	RNA_def_property_flag(prop, PROP_HIDDEN | PROP_SKIP_SAVE);
}

/*********************** cut shape ***************************/

static bool shape_cut_poll(bContext *C)
{
	if (PE_hair_poll(C)) {
		Scene *scene = CTX_data_scene(C);
		ParticleEditSettings *pset = PE_settings(scene);

		if (pset->shape_object && (pset->shape_object->type == OB_MESH)) {
			return true;
		}
	}

	return false;
}

typedef struct PointInsideBVH {
	BVHTreeFromMesh bvhdata;
	int num_hits;
} PointInsideBVH;

static void point_inside_bvh_cb(void *userdata, int index, const BVHTreeRay *ray, BVHTreeRayHit *hit)
{
	PointInsideBVH *data = userdata;

	data->bvhdata.raycast_callback(&data->bvhdata, index, ray, hit);

	if (hit->index != -1)
		++data->num_hits;
}

/* true if the point is inside the shape mesh */
static bool shape_cut_test_point(PEData *data, ParticleCacheKey *key)
{
	BVHTreeFromMesh *shape_bvh = &data->shape_bvh;
	const float dir[3] = {1.0f, 0.0f, 0.0f};
	PointInsideBVH userdata;

	userdata.bvhdata = data->shape_bvh;
	userdata.num_hits = 0;

	BLI_bvhtree_ray_cast_all(
		shape_bvh->tree, key->co, dir, 0.0f, BVH_RAYCAST_DIST_MAX,
		point_inside_bvh_cb, &userdata);

	/* for any point inside a watertight mesh the number of hits is uneven */
	return (userdata.num_hits % 2) == 1;
}

static void shape_cut(PEData *data, int pa_index)
{
	PTCacheEdit *edit = data->edit;
	Object *ob = data->ob;
	ParticleEditSettings *pset = PE_settings(data->scene);
	ParticleCacheKey *key;

	bool cut;
	float cut_time = 1.0;
	int k, totkeys = 1 << pset->draw_step;

	/* don't cut hidden */
	if (edit->points[pa_index].flag & PEP_HIDE)
		return;

	cut = false;

	/* check if root is inside the cut shape */
	key = edit->pathcache[pa_index];
	if (!shape_cut_test_point(data, key)) {
		cut_time = -1.0f;
		cut = true;
	}
	else {
		for (k = 0; k < totkeys; k++, key++) {
			BVHTreeRayHit hit;
			float dir[3];
			float len;

			sub_v3_v3v3(dir, (key + 1)->co, key->co);
			len = normalize_v3(dir);

			memset(&hit, 0, sizeof(hit));
			hit.index = -1;
			hit.dist = len;
			BLI_bvhtree_ray_cast(data->shape_bvh.tree, key->co, dir, 0.0f, &hit, data->shape_bvh.raycast_callback, &data->shape_bvh);
			if (hit.index >= 0) {
				if (hit.dist < len) {
					cut_time = (hit.dist / len + (float)k) / (float)totkeys;
					cut = true;
					break;
				}
			}
		}
	}

	if (cut) {
		if (cut_time < 0.0f) {
			edit->points[pa_index].flag |= PEP_TAG;
		}
		else {
			rekey_particle_to_time(data->context, data->scene, ob, pa_index, cut_time);
			edit->points[pa_index].flag |= PEP_EDIT_RECALC;
		}
	}
}

static int shape_cut_exec(bContext *C, wmOperator *UNUSED(op))
{
	Depsgraph *depsgraph = CTX_data_depsgraph(C);
	Scene *scene = CTX_data_scene(C);
	Object *ob = CTX_data_active_object(C);
	ParticleEditSettings *pset = PE_settings(scene);
	PTCacheEdit *edit = PE_get_current(scene, ob);
	Object *shapeob = pset->shape_object;
	int selected = count_selected_keys(scene, edit);
	int lock_root = pset->flag & PE_LOCK_FIRST;

	if (!PE_start_edit(edit))
		return OPERATOR_CANCELLED;

	/* disable locking temporatily for disconnected hair */
	if (edit->psys && edit->psys->flag & PSYS_GLOBAL_HAIR)
		pset->flag &= ~PE_LOCK_FIRST;

	if (edit->psys && edit->pathcache) {
		PEData data;
		int removed;

		PE_set_data(C, &data);
		if (!PE_create_shape_tree(&data, shapeob)) {
			/* shapeob may not have faces... */
			return OPERATOR_CANCELLED;
		}

		if (selected)
			foreach_selected_point(&data, shape_cut);
		else
			foreach_point(&data, shape_cut);

		removed = remove_tagged_particles(ob, edit->psys, pe_x_mirror(ob));
		recalc_lengths(edit);

		if (removed) {
			update_world_cos(depsgraph, ob, edit);
			psys_free_path_cache(NULL, edit);
			DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
		}
		else {
			PE_update_object(data.depsgraph, scene, ob, 1);
		}

		if (edit->psys) {
			WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_EDITED, ob);
			BKE_particle_batch_cache_dirty_tag(edit->psys, BKE_PARTICLE_BATCH_DIRTY_ALL);
			DEG_id_tag_update(&ob->id, ID_RECALC_SELECT);
		}
		else {
			DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
			WM_event_add_notifier(C, NC_OBJECT | ND_MODIFIER, ob);
		}

		PE_free_shape_tree(&data);
	}

	pset->flag |= lock_root;

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_shape_cut(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Shape Cut";
	ot->idname = "PARTICLE_OT_shape_cut";
	ot->description = "Cut hair to conform to the set shape object";

	/* api callbacks */
	ot->exec = shape_cut_exec;
	ot->poll = shape_cut_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/************************ utilities ******************************/

int PE_minmax(Scene *scene, ViewLayer *view_layer, float min[3], float max[3])
{
	Object *ob = OBACT(view_layer);
	PTCacheEdit *edit = PE_get_current(scene, ob);
	ParticleSystem *psys;
	ParticleSystemModifierData *psmd_eval = NULL;
	POINT_P; KEY_K;
	float co[3], mat[4][4];
	int ok = 0;

	if (!edit) return ok;

	if ((psys = edit->psys))
		psmd_eval = edit->psmd_eval;
	else
		unit_m4(mat);

	LOOP_VISIBLE_POINTS {
		if (psys)
			psys_mat_hair_to_global(ob, psmd_eval->mesh_final, psys->part->from, psys->particles + p, mat);

		LOOP_SELECTED_KEYS {
			copy_v3_v3(co, key->co);
			mul_m4_v3(mat, co);
			DO_MINMAX(co, min, max);
			ok = 1;
		}
	}

	if (!ok) {
		BKE_object_minmax(ob, min, max, true);
		ok = 1;
	}

	return ok;
}

/************************ particle edit toggle operator ************************/

static struct ParticleSystem *psys_eval_get(
        Depsgraph *depsgraph,
        Object *object,
        ParticleSystem *psys)
{
	Object *object_eval = DEG_get_evaluated_object(depsgraph, object);
	if (object_eval == object) {
		return psys;
	}
	ParticleSystem *psys_eval = object_eval->particlesystem.first;
	while (psys_eval != NULL) {
		if (psys_eval->orig_psys == psys) {
			return psys_eval;
		}
		psys_eval = psys_eval->next;
	}
	return psys_eval;
}

/* initialize needed data for bake edit */
void PE_create_particle_edit(
        Depsgraph *depsgraph, Scene *scene, Object *ob, PointCache *cache, ParticleSystem *psys)
{
	Object *ob_eval = DEG_get_evaluated_object(depsgraph, ob);
	PTCacheEdit *edit;
	ParticleSystemModifierData *psmd = (psys) ? psys_get_modifier(ob, psys) : NULL;
	ParticleSystemModifierData *psmd_eval = NULL;
	POINT_P; KEY_K;
	ParticleData *pa = NULL;
	HairKey *hkey;
	int totpoint;

	if (psmd != NULL) {
		psmd_eval = (ParticleSystemModifierData *)modifiers_findByName(ob_eval, psmd->modifier.name);
	}

	/* no psmd->dm happens in case particle system modifier is not enabled */
	if (!(psys && psmd && psmd_eval->mesh_final) && !cache)
		return;

	if (cache && cache->flag & PTCACHE_DISK_CACHE)
		return;

	if (psys == NULL && (cache && BLI_listbase_is_empty(&cache->mem_cache)))
		return;

	edit = (psys) ? psys->edit : cache->edit;

	if (!edit) {
		ParticleSystem *psys_eval = psys_eval_get(depsgraph, ob, psys);
		psys_copy_particles(psys, psys_eval);

		totpoint = psys ? psys->totpart : (int)((PTCacheMem *)cache->mem_cache.first)->totpoint;

		edit = MEM_callocN(sizeof(PTCacheEdit), "PE_create_particle_edit");
		edit->points = MEM_callocN(totpoint * sizeof(PTCacheEditPoint), "PTCacheEditPoints");
		edit->totpoint = totpoint;

		if (psys && !cache) {
			edit->psmd = psmd;
			edit->psmd_eval = psmd_eval;
			psys->edit = edit;
			edit->psys = psys;
			edit->psys_eval = psys_eval;

			psys->free_edit = PE_free_ptcache_edit;

			edit->pathcache = NULL;
			BLI_listbase_clear(&edit->pathcachebufs);

			pa = psys->particles;
			LOOP_POINTS {
				point->totkey = pa->totkey;
				point->keys = MEM_callocN(point->totkey * sizeof(PTCacheEditKey), "ParticleEditKeys");
				point->flag |= PEP_EDIT_RECALC;

				hkey = pa->hair;
				LOOP_KEYS {
					key->co = hkey->co;
					key->time = &hkey->time;
					key->flag = hkey->editflag;
					if (!(psys->flag & PSYS_GLOBAL_HAIR)) {
						key->flag |= PEK_USE_WCO;
						hkey->editflag |= PEK_USE_WCO;
					}

					hkey++;
				}
				pa++;
			}
			update_world_cos(depsgraph, ob, edit);
		}
		else {
			PTCacheMem *pm;
			int totframe = 0;

			cache->edit = edit;
			cache->free_edit = PE_free_ptcache_edit;
			edit->psys = NULL;

			for (pm = cache->mem_cache.first; pm; pm = pm->next)
				totframe++;

			for (pm = cache->mem_cache.first; pm; pm = pm->next) {
				LOOP_POINTS {
					if (BKE_ptcache_mem_pointers_seek(p, pm) == 0)
						continue;

					if (!point->totkey) {
						key = point->keys = MEM_callocN(totframe * sizeof(PTCacheEditKey), "ParticleEditKeys");
						point->flag |= PEP_EDIT_RECALC;
					}
					else
						key = point->keys + point->totkey;

					key->co = pm->cur[BPHYS_DATA_LOCATION];
					key->vel = pm->cur[BPHYS_DATA_VELOCITY];
					key->rot = pm->cur[BPHYS_DATA_ROTATION];
					key->ftime = (float)pm->frame;
					key->time = &key->ftime;
					BKE_ptcache_mem_pointers_incr(pm);

					point->totkey++;
				}
			}
			psys = NULL;
		}

		/* Causes assert on startup. */
#if 0
		UI_GetThemeColor3ubv(TH_EDGE_SELECT, edit->sel_col);
		UI_GetThemeColor3ubv(TH_WIRE, edit->nosel_col);
#else
		memset(edit->sel_col,   0xff, sizeof(edit->sel_col));
		memset(edit->nosel_col, 0x00, sizeof(edit->nosel_col));
#endif
		recalc_lengths(edit);
		if (psys && !cache)
			recalc_emitter_field(depsgraph, ob, psys);

		PE_update_object(depsgraph, scene, ob, 1);
	}
}

static bool particle_edit_toggle_poll(bContext *C)
{
	Object *ob = CTX_data_active_object(C);

	if (ob == NULL || ob->type != OB_MESH)
		return 0;
	if (!ob->data || ID_IS_LINKED(ob->data))
		return 0;
	if (CTX_data_edit_object(C))
		return 0;

	return (ob->particlesystem.first ||
	        modifiers_findByType(ob, eModifierType_Cloth) ||
	        modifiers_findByType(ob, eModifierType_Softbody));
}

static void free_all_psys_edit(Object *object)
{
	for (ParticleSystem *psys = object->particlesystem.first;
	     psys != NULL;
	     psys = psys->next)
	{
		if (psys->edit != NULL) {
			BLI_assert(psys->free_edit != NULL);
			psys->free_edit(psys->edit);
			psys->free_edit = NULL;
			psys->edit = NULL;
		}
	}
}

static int particle_edit_toggle_exec(bContext *C, wmOperator *op)
{
	struct wmMsgBus *mbus = CTX_wm_message_bus(C);
	Depsgraph *depsgraph = CTX_data_depsgraph(C);
	Scene *scene = CTX_data_scene(C);
	Object *ob = CTX_data_active_object(C);
	const int mode_flag = OB_MODE_PARTICLE_EDIT;
	const bool is_mode_set = (ob->mode & mode_flag) != 0;

	if (!is_mode_set) {
		if (!ED_object_mode_compat_set(C, ob, mode_flag, op->reports)) {
			return OPERATOR_CANCELLED;
		}
	}

	if (!is_mode_set) {
		PTCacheEdit *edit;

		ob->mode |= mode_flag;

		edit = PE_create_current(depsgraph, scene, ob);

		/* Mesh may have changed since last entering editmode.
		 * note, this may have run before if the edit data was just created,
		 * so could avoid this and speed up a little. */
		if (edit && edit->psys) {
			/* Make sure pointer to the evaluated modifier data is up to date,
			 * with possible changes applied when object was outside of the
			 * edit mode. */
			Object *object_eval = DEG_get_evaluated_object(depsgraph, ob);
			edit->psmd_eval = (ParticleSystemModifierData *)modifiers_findByName(
			        object_eval, edit->psmd->modifier.name);
			recalc_emitter_field(depsgraph, ob, edit->psys);
		}

		toggle_particle_cursor(C, 1);
		WM_event_add_notifier(C, NC_SCENE | ND_MODE | NS_MODE_PARTICLE, NULL);
	}
	else {
		ob->mode &= ~mode_flag;
		toggle_particle_cursor(C, 0);
		free_all_psys_edit(ob);
		WM_event_add_notifier(C, NC_SCENE | ND_MODE | NS_MODE_OBJECT, NULL);
	}

	DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY | ID_RECALC_COPY_ON_WRITE);

	WM_msg_publish_rna_prop(mbus, &ob->id, ob, Object, mode);

	WM_toolsystem_update_from_context_view3d(C);

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_particle_edit_toggle(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Particle Edit Toggle";
	ot->idname = "PARTICLE_OT_particle_edit_toggle";
	ot->description = "Toggle particle edit mode";

	/* api callbacks */
	ot->exec = particle_edit_toggle_exec;
	ot->poll = particle_edit_toggle_poll;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}


/************************ set editable operator ************************/

static int clear_edited_exec(bContext *C, wmOperator *UNUSED(op))
{
	Object *ob = CTX_data_active_object(C);
	ParticleSystem *psys = psys_get_current(ob);

	if (psys->edit) {
		if (psys->edit->edited || 1) {
			PE_free_ptcache_edit(psys->edit);

			psys->edit = NULL;
			psys->free_edit = NULL;

			psys->recalc |= ID_RECALC_PSYS_RESET;
			psys->flag &= ~PSYS_GLOBAL_HAIR;
			psys->flag &= ~PSYS_EDITED;

			psys_reset(psys, PSYS_RESET_DEPSGRAPH);
			WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_EDITED, ob);
			DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
		}
	}
	else { /* some operation might have protected hair from editing so let's clear the flag */
		psys->recalc |= ID_RECALC_PSYS_RESET;
		psys->flag &= ~PSYS_GLOBAL_HAIR;
		psys->flag &= ~PSYS_EDITED;
		WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_EDITED, ob);
		DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
	}

	return OPERATOR_FINISHED;
}

static int clear_edited_invoke(bContext *C, wmOperator *op, const wmEvent *UNUSED(event))
{
	return WM_operator_confirm_message(C, op, "Lose changes done in particle mode? (no undo)");
}

void PARTICLE_OT_edited_clear(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Clear Edited";
	ot->idname = "PARTICLE_OT_edited_clear";
	ot->description = "Undo all edition performed on the particle system";

	/* api callbacks */
	ot->exec = clear_edited_exec;
	ot->poll = particle_edit_toggle_poll;
	ot->invoke = clear_edited_invoke;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}

/************************ Unify length operator ************************/

static float calculate_point_length(PTCacheEditPoint *point)
{
	float length = 0.0f;
	KEY_K;
	LOOP_KEYS {
		if (k > 0) {
			length += len_v3v3((key - 1)->co, key->co);
		}
	}
	return length;
}

static float calculate_average_length(PTCacheEdit *edit)
{
	int num_selected = 0;
	float total_length = 0;
	POINT_P;
	LOOP_SELECTED_POINTS {
		total_length += calculate_point_length(point);
		++num_selected;
	}
	if (num_selected == 0) {
		return 0.0f;
	}
	return total_length / num_selected;
}

static void scale_point_factor(PTCacheEditPoint *point, float factor)
{
	float orig_prev_co[3], prev_co[3];
	KEY_K;
	LOOP_KEYS {
		if (k == 0) {
			copy_v3_v3(orig_prev_co, key->co);
			copy_v3_v3(prev_co, key->co);
		}
		else {
			float new_co[3];
			float delta[3];

			sub_v3_v3v3(delta, key->co, orig_prev_co);
			mul_v3_fl(delta, factor);
			add_v3_v3v3(new_co, prev_co, delta);

			copy_v3_v3(orig_prev_co, key->co);
			copy_v3_v3(key->co, new_co);
			copy_v3_v3(prev_co, key->co);
		}
	}
	point->flag |= PEP_EDIT_RECALC;
}

static void scale_point_to_length(PTCacheEditPoint *point, float length)
{
	const float point_length = calculate_point_length(point);
	if (point_length != 0.0f) {
		const float factor = length / point_length;
		scale_point_factor(point, factor);
	}
}

static void scale_points_to_length(PTCacheEdit *edit, float length)
{
	POINT_P;
	LOOP_SELECTED_POINTS {
		scale_point_to_length(point, length);
	}
	recalc_lengths(edit);
}

static int unify_length_exec(bContext *C, wmOperator *UNUSED(op))
{
	Object *ob = CTX_data_active_object(C);
	Scene *scene = CTX_data_scene(C);
	Depsgraph *depsgraph = CTX_data_depsgraph(C);

	PTCacheEdit *edit = PE_get_current(scene, ob);
	float average_length = calculate_average_length(edit);

	if (average_length == 0.0f) {
		return OPERATOR_CANCELLED;
	}
	scale_points_to_length(edit, average_length);

	PE_update_object(depsgraph, scene, ob, 1);
	if (edit->psys) {
		WM_event_add_notifier(C, NC_OBJECT | ND_PARTICLE | NA_EDITED, ob);
	}
	else {
		DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
		WM_event_add_notifier(C, NC_OBJECT | ND_MODIFIER, ob);
	}

	return OPERATOR_FINISHED;
}

void PARTICLE_OT_unify_length(struct wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Unify Length";
	ot->idname = "PARTICLE_OT_unify_length";
	ot->description = "Make selected hair the same length";

	/* api callbacks */
	ot->exec = unify_length_exec;
	ot->poll = PE_poll_view3d;

	/* flags */
	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
}
